CN103090971B - Ultra-sensitive time resolution imaging spectrometer and time resolution imaging method thereof - Google Patents

Abstract

The invention relates to an ultra-sensitive time resolution imaging spectrometer which comprises an optics unit and an electricity unit. The optics unit comprises an incidence slit, a light beam expander collimation part, an optics imaging part, a first space light modulator, a second light modulator, a concave mirror, a grating beam split part and a convergence light collecting part. The electricity unit comprises a first random number generator, a second random number generator, a single photon point detector, a counter, a time measuring meter, a control module, a data package storer and a compression sensing module. Pianissimo light to be measured incidence is changed to parallel light through the light beam expander collimation part, a transmission optical imaging component is imaged on the first space light modulator which conducts random modulating, the concave mirror enables the incident light to be reflected, collimated and changed to the parallel light, the grating beam split part is hit by the concave mirror to form a spectral field, a spectrum band is formed on the second light modulator which conducts random modulation for the spectrum band, the convergence light collecting part filter stray light, and after filtering, the light is transmitted on the single photon point detector.

Description

A kind of hypersensitive Time-resolved imaging spectrometer and Time-resolved imaging method thereof

Technical field

The present invention relates to optical field, particularly a kind of hypersensitive Time-resolved imaging spectrometer and Time-resolved imaging method thereof.

Background technology

Current, the technology that international present stage is used for measuring the transient state pole low light level (as fluorescence lifetime) mainly contains single-molecule detection technology, TIME RESOLVED TECHNIQUE and super-resolution measuring technique.Wherein: (1) single-molecule detection technology mainly contains wide field confocal fluorescent microtechnic, scanning near-field optical micro-(SNOM) technology, total internal reflection fluorescent micro-(TIRF) technology, atomic force optical microphotograph (AFOM) and Raman scattering techniques; (2) TIME RESOLVED TECHNIQUE mainly contains fluorescence lifetime imaging (FLIM), two-photon fluorescence life-span micro-imaging, fluorescence lifetime correlation spectrum (FCS) technology and various dimensions fluorescence lifetime microtechnic; (3) super-resolution measuring technique mainly contains stimulated emission depletion micro-(STED) technology, position sensing micro-(PALM, STORM, dSTORM, GSDIM) technology, micro-(SOFI) technology of optics fluctuation and FRET (fluorescence resonance energy transfer) microtechnic (FRET).

For the fluorescence lifetime imaging of biomacromolecule and related spectral quantification measuring method be, first carry out single-point fluorescence lifetime and correlation spectrum measurement by FLIM or FCS system, then, laser beam flying or specimen scanning system is adopted to carry out biomacromolecule fluorescence lifetime and correlation spectrum imaging measurement.Due to poor stability, the scanning process complexity of nanometer displacement scanning platform, not only increase manufacturing cost, also greatly extend the test duration of nano material and biomacromolecule, success ratio is also subject to appreciable impact.For nano material high resolving power microstructure imaging measurement method, normally adopt scanning electron microscope to carry out profiles characteristic, because high energy electron ionization can damage sample, the noninvasive imaging that cannot carry out bioactive molecule and nano material is measured.Simultaneously the common fault of these technology above-mentioned cannot carry out correlation spectroscopy and time resolution work to object of observation.Along with scientific research demand gradually to high time resolution, multiband, detection fast, the future development such as photon excitation, these functions seem all the more and cannot meet growing actual demand, can carry out spectral analysis and time-resolved instrument in the urgent need to one to object of observation simultaneously.

Summary of the invention

The object of the invention is to overcome existing instrument cannot carry out spectral analysis and time-resolved defect to object of observation simultaneously, thus a kind of device that simultaneously can realize spectral analysis and Time-resolved imaging is provided.

To achieve these goals, the invention provides a kind of hypersensitive Time-resolved imaging spectrometer, comprise optical unit I and electrical units II, wherein, described optical unit I comprises entrance slit 1, light beam-expanding collimation parts 2, optical imagery parts 3, first spatial light modulator 4_1, concave mirror 5, grating beam splitting parts 6, second space photomodulator 4_2, assembles light absorbing part part 7; Described electrical units II comprises the first randomizer 10_1, the second randomizer 10_2, single photon point probe 11, counter 12, time measuring instrument 13, control module 15, packet memory 16 and compressed sensing module 17;

Other pole to be measured low light level of single-photon-level is incident by described entrance slit 1, then after the expanding and collimate of described smooth beam-expanding collimation parts 2, become directional light, this directional light is imaged on described first spatial light modulator 4_1 through described optical imagery parts 3 again; Described first spatial light modulator 4_1 does Stochastic Modulation to picture thereon, and its emergent light is reflected to described concave mirror 5 with certain random chance; Described concave mirror 5 is by reflected incident light and collimate, and makes it again to become directional light, beats to described grating beam splitting parts 6; Described grating beam splitting parts 6 form spectrum field, and second space photomodulator 4_2 on the focal plane being positioned at described grating beam splitting parts 6 forms band; Described second space photomodulator 4_2 does Stochastic Modulation to band thereon, and emergent light is reflected to described convergence light absorbing part part 7 with necessarily random probability; Described convergence light absorbing part part 7 filtering parasitic light, by the pole to be measured poor optical transmission after filtration to the single photon point probe 11 in electrical units II;

Described first randomizer 10_1, the second randomizer 10_2 generate random number respectively and are supplied to described first spatial light modulator 4_1 and second space photomodulator 4_2 respectively, in each spatial light modulator, the random number of the total length in pixels in region forms a corresponding random base, and described first spatial light modulator 4_1 and second space photomodulator 4_2 realizes Stochastic Modulation according to respective random base; Described single photon point probe 11 detects each single photon point in the low light level of pole to be measured, exports after converting the light signal collected to effective impulse signal; Described counter 12 records the number of the single photon point that described single photon point probe 11 detects; The temporal information that described time measuring instrument 13 record photon point arrives; Described control module 15 is carried out control to whole hypersensitive Time-resolved imaging spectrometer and is coordinated, comprise and the enable of each parts and trigger pulse are controlled, guarantee counter 12, first spatial light modulator 4_1, step between second space photomodulator 4_2 and time measuring instrument 13 coordinates; The temporal information that the number of the single photon point that described counter 12 records, time measuring instrument 13 record and two groups of random bases that the first randomizer 10_1, the second randomizer 10_2 generate are together stored in described packet memory 16, finally import in described compressed sensing module 17, calculate through twice compressed sensing in this module, realize band signal reconstruction, export the Time-resolved imaging spectrum containing five-dimensional information.

In technique scheme, described optical unit I also comprises catoptron 8 and exit slit 9; Described catoptron 8 between described grating beam splitting parts 6 and the light path of described second space photomodulator 4_2, for by spectral reflectance to exit slit 9.

In technique scheme, described electrical units II also comprises digital delay 14, and described digital delay 14, under the control of described control module 15, completes the picosecond gate to described single photon point probe 11.

In technique scheme, the described Time-resolved imaging spectrum containing five-dimensional information comprise following any one or multiple: spectral intensity curve (λ, I), time resolved spectroscopy intensity map (λ, I, t), hypersensitive two-dimensional imaging (x, y), hypersensitive three-dimensional imaging (x, y, z), hypersensitive two-dimensional imaging spectrum (x, y, λ), hypersensitive time resolution two-dimensional imaging (x, y, t), hypersensitive three-dimensional imaging spectrum (x, y, z, λ), hypersensitive time resolution three-dimensional imaging (x, y, z, t), hypersensitive time resolution two-dimensional imaging spectrum (x, y, λ, t) with hypersensitive time resolution three-dimensional imaging spectrum (x, y, z, λ, t), wherein, I represents light intensity, and λ represents wavelength, and x, y, z representation space three-dimensional coordinate, t represents the time.

In technique scheme, the light field of different wave length projects the diverse location of described second space photomodulator 4_2 from being short to length by wavelength by described grating beam splitting parts 6 successively.

In technique scheme, described first spatial light modulator 4_1, second space photomodulator 4_2 adopt Digital Micromirror Device to realize.

In technique scheme, using the image space of the diagonal line of described Digital Micromirror Device as described band.

In technique scheme, described convergence light absorbing part part 7 comprises optical filter and attenuator.

In technique scheme, described single photon point probe 11 adopts Geiger mode avalanche diode or photomultiplier to realize.

In technique scheme, described time measuring instrument 13 adopt with time to amplitude converter function time correlation numbered card or independently time to amplitude converter realize.

In technique scheme, described control module 15 guarantees that counter 12, first spatial light modulator 4_1, step between second space photomodulator 4_2 and time measuring instrument 13 are coordinated to comprise: first keep described first spatial light modulator 4_1 constant, described second space photomodulator 4_2 overturns at random, micro mirror array in described second space photomodulator 4_2 often overturns once, all photons that the stored counts of described counter 12 detected in interval in this flip-flop transition, after having overturn, counter 12 resets; After described second space photomodulator 4_2 completes one group of measurement, described first spatial light modulator 4_1 is turned to next frame more at random, repeats aforesaid operations, until the frame number that described first spatial light modulator 4_1 overturns reaches requirement.

In technique scheme, described compressed sensing module 17 adopt in following algorithm any one realize compressed sensing: greedy reconstruction algorithm, Matching pursuitalgorithm MP, orthogonal Matching pursuitalgorithm OMP, base track algorithm BP, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm.

Present invention also offers a kind of Time-resolved imaging method based on described hypersensitive Time-resolved imaging spectrometer, for realizing the time resolution of the long-term sequence to change non-periodic, comprising:

Step 1), the step of single-photon incident;

Other pole to be measured low light level of single-photon-level is incident by described entrance slit 1, then after the expanding and collimate of described smooth beam-expanding collimation parts 2, become directional light, this directional light is imaged on described first spatial light modulator 4_1 through described optical imagery parts 3 again; Described first spatial light modulator 4_1 does Stochastic Modulation to picture thereon, and its emergent light is reflected to described concave mirror 5 with certain random chance; Described concave mirror 5 is by reflected incident light and collimate, and makes it again to become directional light, beats to described grating beam splitting parts 6; Described grating beam splitting parts 6 form spectrum field, and second space photomodulator 4_2 on the focal plane being positioned at described grating beam splitting parts 6 forms band; Described second space photomodulator 4_2 does Stochastic Modulation to band thereon, and emergent light is reflected to described convergence light absorbing part part 7 with necessarily random probability; Described convergence light absorbing part part 7 filtering parasitic light, by the pole to be measured poor optical transmission after filtration to the single photon point probe 11 in electrical units II;

Step 2), detect single photon and counting step;

Single photon point probe 11 detects each single photon point of object under test, exports after converting the light signal collected to effective impulse signal; Also be not able to do in time in the time interval of change at the pole to be measured low light level, first keep described first spatial light modulator 4_1 constant, described second space photomodulator 4_2 overturns repeatedly at random, counter 12 record reaches the number of the single photon point on described single photon spot detector 11, after completing one group of measurement, described first spatial light modulator 4_1 is turned to next frame more at random, it can be used as measured value;

Step 3), the step of compressed sensing;

The random base one_to_one corresponding that the number of the single photon point that described counter 12 records and described randomizer 10_2 generate, be packaged in described packet memory 16 together, finally import in described compressed sensing module 17, in this module, realize band signal reconstruction, recover the image in this time interval;

Step 4), after object under test changes in the time interval also not occurring once to change, repeat aforesaid operations, realize the time resolution of long-term sequence process of change non-periodic.

The present invention also been proposed a kind of Time-resolved imaging method based on time interval measurement realized based on described hypersensitive Time-resolved imaging spectrometer, for being that the transient process of 1.5ms ~ 5ms carries out time resolution to the cycle; Comprise:

Step 1), suppose that the transient state cycle is T, is divided into d the time interval this time cycle, is denoted as t ₁, t ₂, t ₃..., t _d, in this cycle T, keep described first spatial light modulator 4_1 and second space photomodulator 4_2 all to fix a frame constant;

Step 2), the step of single-photon incident;

Step 3), detect single photon and counting step;

Described single photon point probe 11 is to dropping on t _isingle photon in the time interval detects, the monochromatic light subnumber in every period of time interval recorded by described counter 12, the timing code recorded with described time measuring instrument 13 is combined as a packet, before upper once laser pulse is launched, micro mirror array instant reverse in described spatial light modulator 4_2 is to next frame, and described spatial light modulator 4_1 still keeps original state, so repeat P operation equally, each t _ithe time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, then judge whether the upset frame number of micro mirror array in described spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 4), otherwise in described spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-executes step 1); K is wherein the degree of rarefication of imaging on spatial light modulator 4_1, and N is the pixel size of imaging on spatial light modulator 4_1;

Step 4), the step of compressed sensing;

According to step 3) result that obtains, do algorithm to d the time interval respectively to rebuild, be finally inversed by the spectral intensity change procedure in the transient state cycle, obtain time resolved spectroscopy intensity map, again using the intensity of wavelength corresponding to each moment spectrum as measured value, again import compressed sensing algoritic module 17 to calculate together with the stochastic matrix generated in described first randomizer 10_1, obtain the two dimensional image under this wavelength of this moment, and then obtain Time-resolved imaging spectrum.

The invention allows for a kind of Time-resolved imaging method based on delay measurements realized based on described hypersensitive Time-resolved imaging spectrometer, for being that the transient process of 80ns ~ 1.5ms carries out time resolution to the cycle; The method comprises:

Step 1), first to keep described first spatial light modulator 4_1 and second space photomodulator 4_2 all to fix a frame constant, keep the initiating terminal of the gate-width of single photon point probe 11 to overlap with transient state period start time, gate-width is less than transient state cycle T;

Step 2), the cycle is when starting, single-photon incident;

Step 3), described single photon point probe 11 and time measuring instrument 13 start to measure simultaneously, only detect once within this transient state cycle, measured count value is gate-width and the monochromatic light subnumber in this overlapping time period in transient state cycle, successively repeat Q time, then Corpus--based Method principle each counting is added with;

Step 4), utilize described digital delay 14 that gate-width is increased 20ps, re-execute step 3) obtain another counting add and, to add and as with reference to value using first, second add and with first add and difference as the statistical counting in that gate-width period extended, obtain the d section statistical counting between the reference point moment to transient state end cycle moment;

Step 5), keep gate-width constant, in advance the due in of gate-width, re-executes step 3) with step 4), using a series of count difference values of obtaining as start time in transient state cycle to the reference point moment between d section statistical counting;

Step 6), according to step 4) d section statistical counting between reference point moment to transient state end cycle moment of obtaining and step 5) d section statistical counting between start time in transient state cycle to reference point moment of obtaining, obtain the segmentation statistical counting in the whole transient state cycle;

Step 7), micro mirror array instant reverse in described spatial light modulator 4_2 is to next frame, and spatial light modulator 4_1 still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, after aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in described spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 8), otherwise, in spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-execute step 1), K is wherein the degree of rarefication of imaging on spatial light modulator 4_1, and N is the pixel size of imaging on spatial light modulator 4_1,

Step 8), the step of compressed sensing;

According to step 7) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.

The present invention also been proposed a kind of Time-resolved imaging method based on photon time of arrival realized based on described hypersensitive Time-resolved imaging spectrometer, comprising:

Step 1), the time to amplitude converter reference pulse be supplied in described time measuring instrument 13, then described first spatial light modulator 4_1 and second space photomodulator 4_2 is kept all to fix a frame constant, utilize described time to amplitude converter that the time obtaining photon is recorded in the form of voltage, be recorded in corresponding time channel, and reach the time by photon number segmentation division by photon, count the d section stored counts in one-period in each time interval;

Step 2), micro mirror array instant reverse in described second space photomodulator 4_2 is to next frame, and the first spatial light modulator 4_1 still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, respectively a corresponding P stochastic matrix; After aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in the first spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 3), otherwise, in first spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-executes step 1); K is wherein the degree of rarefication of imaging on the first spatial light modulator 4_1, and N is the pixel size of imaging on the first spatial light modulator 4_1;

Step 3), the step of compressed sensing;

According to step 2) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.

The invention has the advantages that:

1, the present invention utilizes single-photon detecting survey technology, the single photon counting data of acquisition is temporally divided into groups, utilizes compressive sensing theory, and grouping is reconstructed and realizes hypersensitive Time-resolved imaging spectrum.

2, traditional linear array or array detection device are replaced as spatial light modulator and add single photon point probe by the present invention, allow light spectrum image-forming in spatial modulator, then single photon point probe receives, brand-new time discrimination measurement method is combined with compressive sensing theory, greatly save dimension, without the need to raster scanning, reduce measurement scale

3, the spectral measurement that the present invention is directed to the transient state cycle also proposes three kinds of brand-new time discrimination measurement methods based on compressed sensing principle: the time resolution method based on time interval measurement, the time resolution method based on delay measurements and the time resolution method based on photon time of arrival, make time resolution precision reach picosecond magnitude.

4, the photon that the present invention utilizes time resolution to obtain to extrapolate the optical path difference in the distance of space time of arrival, and obtain the dimensional information of third spatial dimension, realize three-dimensional imaging, longitudinal frame reaches a millimeter magnitude, and flat resolution can reach nanometer scale.

5, on the light flux ratio tradition linear array on the single photon point probe in the present invention or detector array, luminous flux is high on unit pixel, and rebuild by the light signal of compressed sensing algorithm, its spectrally resolved ability is higher, spatial resolving power is higher.

6, system of the present invention can be applicable to the emerging high-tech areas such as time resolved spectroscopy imaging, time-resolved fluorescence micro-imaging, celestial spectrum analysis, biological cell detection, nano material spectral analysis, biomechanism checking.

Accompanying drawing explanation

Fig. 1 is the overall construction drawing of hypersensitive Time-resolved imaging spectrometer of the present invention;

Fig. 2 is the getable Time-resolved imaging spectrogram of hypersensitive Time-resolved imaging spectrometer of the present invention;

Fig. 3 is the reflex mechanism schematic diagram of the single micro mirror in digital micro-mirror;

Fig. 4 is the time resolved spectroscopy schematic diagram of Digital Micromirror Device in second space photomodulator;

Fig. 5 is the Time-resolved imaging method block diagram based on time interval measurement;

Fig. 6 is a point time interval record photon number schematic diagram;

Fig. 7 is the Time-resolved imaging method block diagram based on delay measurements;

Fig. 8 is that statistics makes single photon counting schematic diagram in the difference rear time interval.

Embodiment

Now the invention will be further described by reference to the accompanying drawings.

Before the present invention is elaborated, first corresponding explanation is done to related notion involved in the present invention.

Time resolution: refer to that the transient process observing physics and chemistry also can differentiate its time.

Compressed sensing (Compressive Sensing, be called for short CS) principle: described compressed sensing principle is the brand-new mathematical theory proposed by people such as Donoho, Tao and Candes, in the mode of stochastic sampling, ideally recover original signal by less data sampling number (limit far below Nyquist/Shannon's sampling theorem), and higher robustness can be had according to this theory.Compressed sensing is mainly divided into three steps: compression sampling, sparse transformation and algorithm are rebuild; Wherein, compression sampling, refers to that measured signal is mapped and the process gathered to low-dimensional by higher-dimension; Described sparse transformation chooses suitable factor Ψ, and it is sparse for making x change income value x ' through Ψ, and namely x can sparse expression under Ψ framework; It is the process solving y=A Ψ x'+e under the condition of known observation data y, calculation matrix A and framework Ψ that described algorithm is rebuild, finally again by be finally inversed by x.

Concept involved in the present invention elaborates to hypersensitive Time-resolved imaging spectrometer of the present invention after doing unified explanation below.

With reference to figure 1, hypersensitive Time-resolved imaging spectrometer of the present invention comprises optical unit I (in Fig. 1 in rectangular broken line frame part) and electrical units II, wherein, optical unit I comprises entrance slit 1, light beam-expanding collimation parts 2, optical imagery parts 3, first spatial light modulator 4_1, concave mirror 5, grating beam splitting parts 6, second space photomodulator 4_2, assembles light absorbing part part 7, catoptron 8 and exit slit 9.Electrical units II comprises the first randomizer 10_1, the second randomizer 10_2, single photon point probe 11, counter 12, time measuring instrument 13, control module 15, packet memory 16 and compressed sensing module 17.

In optical unit I, other pole to be measured low light level of single-photon-level enters hypersensitive Time-resolved imaging spectrometer by entrance slit 1, then after the expanding and collimate of light beam-expanding collimation parts 2, become directional light, this directional light is imaged on the first spatial light modulator 4_1 through optical imagery parts 3 again; After first spatial light modulator 4_1 loads the random number that the first randomizer 10_1 generates, Stochastic Modulation is done to picture thereon, its emergent light is reflected to concave mirror 5 with certain random chance; Concave mirror 5 is by reflected incident light and collimate, and makes it again to become directional light, beats to grating beam splitting parts 6 and covers whole grating face as far as possible; Described grating beam splitting parts 6 form spectrum field, and second space photomodulator 4_2 on the focal plane being positioned at grating beam splitting parts 6 forms band, thus the light of different wave length implementation space on focal plane is separated; Described second space photomodulator 4_2 loads the random number that the second randomizer 10_2 generates, thus does Stochastic Modulation to band thereon, and emergent light is reflected to convergence light absorbing part part 7 with necessarily random probability; Described convergence light absorbing part part 7 for filtering parasitic light, by filter after pole to be measured poor optical transmission to the single photon point probe 11 in electrical units II; Described catoptron 8 between grating beam splitting parts 6 and the light path of second space photomodulator 4_2, for by spectral reflectance to exit slit 9, receive for other type of sensors or enter other optical system and carry out measuring study.

In electrical units II, first randomizer 10_1, the second randomizer 10_2 are respectively used to generate random number, the random number produced is supplied to the first spatial light modulator 4_1 and second space photomodulator 4_2 respectively, in each spatial light modulator, the random number of the total length in pixels in region forms a random base, and described first spatial light modulator 4_1 and second space photomodulator 4_2 realizes Stochastic Modulation according to respective random base, described single photon point probe 11, for detecting each single photon point in the low light level of pole to be measured, exports after converting the light signal collected to effective impulse signal, the number of the single photon point that described counter 12 detects for record photon point probe 11, the temporal information that described time measuring instrument 13 arrives for recording single photon point, described control module 15 is coordinated for carrying out control to whole hypersensitive Time-resolved imaging spectrometer, comprise and the enable of each parts and trigger pulse are controlled, guarantee that counter 12, first spatial light modulator 4_1, step between second space photomodulator 4_2 and time measuring instrument 13 are coordinated, remove the asynchronous time difference if desired, the number of the single photon point that counter 12 records, the temporal information that time measuring instrument 13 records and the first randomizer 10_1, two groups of random base one_to_one corresponding that second randomizer 10_2 generates, be packaged in packet memory 16 together, finally import in compressed sensing module 17, calculate through twice compressed sensing in this module, realize band signal reconstruction, output spectrum intensity curve (λ, I), time resolved spectroscopy intensity map (λ, I, t), hypersensitive two-dimensional imaging (x, y), hypersensitive three-dimensional imaging (x, y, z), hypersensitive two-dimensional imaging spectrum (x, y, λ), hypersensitive time resolution two-dimensional imaging (as fluorescence lifetime) (x, y, t), hypersensitive three-dimensional imaging spectrum (x, y, z, λ), hypersensitive time resolution three-dimensional imaging (x, y, z, t), hypersensitive time resolution two-dimensional imaging spectrum (x, y, λ, t) with hypersensitive time resolution three-dimensional imaging spectrum (x, y, z, λ, ten kinds of results such as t), namely containing the Time-resolved imaging spectrum of five-dimensional information.

It is more than the description of the general structure to hypersensitive Time-resolved imaging spectrometer of the present invention in an embodiment, in another embodiment, hypersensitive Time-resolved imaging spectrometer of the present invention also includes digital delay 14, described digital delay 14 under the control of control module 15, for completing the picosecond gate to single photon point probe 11.In other embodiments, hypersensitive Time-resolved imaging spectrometer of the present invention can not also comprise catoptron 8 and exit slit 9.

Below the specific implementation of all parts in spectrometer is further described.

Slit is the gap formed on light-path by a pair dividing plate, and entrance slit 1 is for regulating purity and the intensity of incident light, and form the object point of spectrometer, exit slit 9 is for bright dipping.

Described grating beam splitting parts 6 are for spectrum, these parts adopt the working method of dispersion formula light splitting, the light field of different wave length projects the diverse location of second space photomodulator 4_2 by wavelength from being short to length by dispersion element (prism or grating) in grating beam splitting parts 6 successively, without the need to scanning, each spectral band obtains simultaneously.In this spectroscopic modes, the height of spectral resolution is directly proportional to the collimation of the incident light arriving dispersion element (prism or grating), and the better spectral resolution of collimation is higher.In the present embodiment, described grating beam splitting parts 6 adopt blazed grating to realize.

Information can load on the optical data field of one dimension or bidimensional by described first spatial light modulator 4_1 and second space photomodulator 4_2, it is the Primary Component in the contemporary optics fields such as real-time optical information processing, adaptive optics and optical oomputing, this kind of device can under the control of time dependent electric drive signal or other signals, change spatially photodistributed amplitude or intensity, phase place, polarization state and wavelength, or incoherent light is changed into coherent light.Its kind has a variety of, mainly contains Digital Micromirror Device (Digital Micro-mirror Device is called for short DMD), frosted glass, liquid crystal light valve etc.In the present embodiment, described SLM is Digital Micromirror Device, comprises micro mirror array and Integrated circuit portion.In other embodiments, also can be the SLM of other type.

The DMD adopted in the present embodiment includes the thousands of array being arranged on the micro mirror on hinge (DMD of main flow is made up of the array of 1024 × 768, maximum can to 2048 × 1152), each eyeglass is of a size of 14 μm × 14 μm (or 16 μm × 16 μm) and can the light of a break-make pixel, these micro mirrors all left floating, by carrying out electronic addressing to the storage unit under each eyeglass with binarization plane signal, just each eyeglass can be allowed to both sides to tilt about 10 ~ 12 ° (in the present embodiment, getting+12 ° and-12 °) for electrostatically, this two states is designated as 1 and 0, corresponding "ON" and "Off" respectively, when eyeglass does not work, they are in " berthing " state of 0 °.

In figure 3, the reflex mechanism of the single micro mirror in DMD is described.Baseline when fine line in figure represents single micro mirror initial position and normal, get and just clockwise turn to, and is negative counterclockwise.When the initial normal of incident ray and this becomes 24 °, reflection ray also becomes 24 ° with initial normal, but when micro mirror upset+12 °, in this legend, the normal of micro mirror turns clockwise+12 ° thereupon, according to reflection law, reflection ray then needs to turn clockwise+24 °, namely with initial normal on the same line, the receive direction that this initial normal direction is single photon point probe 11 can be set.In like manner, when micro mirror upset-12 °, reflection ray at this moment becomes-48 ° with initial normal, almost can not receive by coverlet photon point probe 11, can ignore.Certain receive direction also can be set to exit direction during micro mirror-12 ° upset.

It should be noted that, for making the resolution length of band long as far as possible, optionally take diagonal line in the DMD realizing second space photomodulator 4_2 as the image space of band, and the reverses direction of each micro mirror is just diagonal in DMD, if using DMD diagonal line as horizontal direction, also in the horizontal direction, the pixel that this method obtains is maximum, and the DMD diagonal line of such as 2048 × 1152 sizes is reducible reaches 2350 pixels for band image space.

Assemble light absorbing part part 7 and comprise optical filter and attenuator, described optical filter is used for the parasitic light in filtering light-metering to be checked, when light ratio to be detected is stronger, the combination of many group attenuators need be adopted to carry out optical attenuation, to prevent single photon point probe 11 saturated.

In the present embodiment, described single photon point probe 11 adopts Geiger mode avalanche diode (avalanche photodiode, be called for short APD), in other embodiments, this point probe also replaceable one-tenth other there is the point probe of single photon detection ability, as photomultiplier Photomultiplier tube (PMT).

Described time measuring instrument 13 adopts with time to amplitude converter (Time to Amplitude Converter, be called for short TAC) the time correlation numbered card (Time-correlated Single Photon Counting Module, be called for short TCSPC) of function or independently time to amplitude converter realize.

The control that described control module 15 realizes refers to that the enable of each parts and trigger pulse control, flip-flop number 12 resets and stored counts again, the coordination that this module realizes mainly realizes counter 12 and the first spatial light modulator 4_1, step between second space photomodulator 4_2 is coordinated, namely first keep the first spatial light modulator 4_1 constant, second space photomodulator 4_2 overturns at random, micro mirror array in second space photomodulator 4_2 often overturns once, all photons that counter 12 stored counts detected in interval in this flip-flop transition, after having overturn, counter 12 resets, after second space photomodulator 4_2 completes one group of measurement, the first spatial light modulator 4_1 is turned to next frame more at random, repeats aforesaid operations, until the frame number that the first spatial light modulator 4_1 overturns reaches requirement.The temporal information that last all counting, the time measuring instrument 13 obtained records and the stochastic matrix (random base) that random-number-generating module 10 produces are packed and are reached in packet memory 16.

The count value that described compressed sensing module 17 obtains according to counter 12, second random measurement matrix (are made up of the some random base in the second randomizer 10_2, and single random base is stretched by certain stochastic matrix to obtain), only a small amount of linear random projection of light requirement bands of a spectrum just can reconstruct spectral intensity; On band each point in the light intensity in this moment as indirect measurement, participate in reconstruction algorithm with first random measurement matrix (being made up of the some random base in the first randomizer 10_1) to calculate, recover image information, and utilize the theoretical signal deletion made up in band of matrix fill-in, then the timing code that binding time measuring instrument 13 records (stamp) just exportable Time-resolved imaging spectrum.Wherein, described sparse transformation chooses suitable Ψ, makes band signal x can sparse expression under Ψ framework.The algorithm adopted during compressed sensing has multiple, comprises greedy reconstruction algorithm, Matching pursuitalgorithm MP, orthogonal Matching pursuitalgorithm OMP, base track algorithm BP, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm etc., any one adopting in above-mentioned algorithm all can realize the present invention.

Do one to the course of work of compressed sensing module 17 to be below described in further detail.

Suppose x ∈ R ⁿmeasured data, y ∈ R ^kobservation data, A ∈ R ^{k × N}random measurement matrix (K < <), e ∈ R ^kbe noise of instrument, K is the number of the nonzero element in x, also claims degree of rarefication, and so, the process of compression sampling can be described as (1) formula:

y＝Ax+e (1)

If x is compressible or can sparse expression, then be sparse transformation matrix, also claim framework or dictionary, so (1) formula is changed to (2) formula:

y＝AΨx'+e (2)

Wherein A Ψ meets RIP criterion.

The sum of all pixels making two dimensional image region (including whole band) is N, then the calculation matrix in (1) formula is then A=[a ₁, a ₂..., a _n], be made up of 1 and 0, amount to M dimension, be i.e. the matrix of the capable N row of M, a _iit is i-th row of A.Joined end to end by the row in the two dimensional image region of p × q pixel, change into a dimensional vector of N × 1 (wherein N=p × q), the x in corresponding (1) formula, each element wherein represents the light intensity of corresponding position.During order each upset, the row of micro mirror array joins end to end, and changes into the one dimension row vector of 1 × N, a line in corresponding calculation matrix A, and whether it 1 and 0 represents corresponding position micro mirror and overturn to single photon point probe 11 direction.

Micro mirror array in second space photomodulator 4_2 starts random upset, the photon number that each single photon point probe 11 detects is designated as count, be equivalent to the interior sum of random base and former specrtal band intensity, an element of vectorial y is observed in (1) formula of corresponding to, repeat K time to measure, just can obtain whole group of observation data y (y is a dimensional vector of K × 1).

Described sparse transformation chooses suitable Ψ, it is sparse for making x change income value x ' through Ψ, namely x can sparse expression under Ψ framework, and algorithm reconstruction solves the x in (1) formula under the condition of known observation data y and calculation matrix A, as M < N, this is a NP-hard problem, but utilizes compressed sensing algorithm can transfer convex optimization problem to solve, and wherein a kind of common normal form is expressed as (3) formula:

$\underset{x^{\&prime;}}{\min }\frac{1}{2}{\left|\right|y-\mathrm{A\&Psi;}{x}^{\&prime;}\left|\right|}_2^2+\mathrm{\&tau;}{\left|\right|x^{\&prime;}\left|\right|}_1---\left(3\right)$

Wherein || ... || _prepresent norm operator, section 1 is least square constraint, and be designated as f (x), Section 2 retrains the one of x degree of rarefication, and two sums are objective functions.Only need M≤O (Klog (N/K)) secondary measurement, just can the original light intensity signal of perfect reconstruction, coordinate with wavelength corresponding to the upper pixel demarcated of the Digital Micromirror Device (DMD) in second space photomodulator 4_2, just spectral intensity curve (λ can be recovered, I), in addition with time discrimination measurement method, just can rise time resolved spectroscopy intensity map (λ, I, t); If the light intensity intercepted under a certain wavelength carries out Recovery image, just hypersensitive two-dimensional imaging (x, y) can be obtained; If the photon obtained by the time to amplitude converter in time measuring instrument 13 converts the far and near information of spatial depth to time of arrival, then can obtain hypersensitive three-dimensional imaging (x, y, z); If reconstruct two dimensional image respectively to the light intensity under each wavelength, just can obtain the change profile of two dimensional image with wavelength, i.e. hypersensitive two-dimensional imaging spectrum (x, y, λ); If the light intensity intercepted under a certain wavelength carries out Recovery image, and temporally resolved measurement method observes this wavelength hypograph over time, just obtain hypersensitive time resolution two-dimensional imaging (as fluorescence lifetime) (x, y, t); If coordinate with grating beam splitting on hypersensitive three-dimensional imaging basis, and then obtain 3-D view at different wavelengths, i.e. hypersensitive three-dimensional imaging spectrum (x, y, z, λ); If add the dimensional information of photon time of arrival on hypersensitive three-dimensional imaging basis, just can obtain the three-dimensional reconstruction image in each sub-time period, i.e. hypersensitive time resolution three-dimensional imaging (x, y, z, t); If add the dimensional information of photon time of arrival on the basis of hypersensitive two-dimensional imaging spectrum, image is reconstructed to the object under test under each wavelength in each sub-time period, just can obtain hypersensitive time resolution two-dimensional imaging spectrum (x, y, λ, t); If coordinate with grating beam splitting on hypersensitive time resolution three-dimensional imaging basis, and then obtain time resolution 3-D view at different wavelengths, i.e. hypersensitive time resolution three-dimensional imaging spectrum (x, y, z, λ, t).

Fig. 2 be hypersensitive Time-resolved imaging spectrometer of the present invention the schematic diagram of getable Time-resolved imaging rebuilding spectrum figure, exemplarily, it is the cell sample between below pig epidermis 5 μm to 60 μm in figure, exemplarily analyze, extract plot of light intensity picture corresponding under a certain wavelength, provide with the form of gray-scale map, the size of gray-scale value is to should the power of light intensity under wavelength, time resolution precision reaches picosecond magnitude, in legend can its imaging spectral of clear resolution along with the evolution process of time.Its essence is the image-forming spectral measurement with space two-dimensional, light intensity, time resolution, spectrally resolved five dimension parameter information.

It is more than the structure explanation to hypersensitive Time-resolved imaging spectrometer of the present invention.Below the course of work of this hypersensitive Time-resolved imaging spectrometer is described.

Hypersensitive Time-resolved imaging spectrometer of the present invention, for different application scenarioss, can adopt diverse ways to realize Time-resolved imaging, be explained respectively below.

1, the long-term sequence of change non-periodic

For the long-term sequence process of change non-periodic, namely object under test changes slowly and changes the non-periodic that is changed to occurred, based on hypersensitive Time-resolved imaging spectrometer of the present invention, adopt the method that a frame frame sequential is measured, namely when having surveyed the first frame spectral intensity sequence, then surveying next frame spectral intensity sequence, being recovered the spectral intensity curve of each frame by compressed sensing algorithm, just realize increasing time dimension on spectral intensity curve, finally obtain time resolved spectroscopy intensity map.

Wherein the concrete measuring process of each frame spectral intensity sequence is as follows:

Step 1), the step of single-photon incident.

In the interval sometime that the pole to be measured low light level does not change, the pole to be measured low light level enters hypersensitive Time-resolved imaging spectrometer by entrance slit 1, after the expanding and collimate of light beam-expanding collimation parts 2, become directional light.Quasi-parallel light is imaged on the first spatial light modulator 4_1 through optical imagery parts 3 again, and by its Stochastic Modulation, some light enters towards the direction of concave mirror 5 (i.e. grating beam splitting parts 6 can receive direction).This light reflects and collimates by concave mirror 5, makes it again to become directional light, beats to grating beam splitting parts 6 and covers whole grating face as far as possible.Be positioned on the focal plane of grating beam splitting parts 6 by second space photomodulator 4_2, so spectrum field will be imaged on second space photomodulator 4_2, the light of different wave length just can be separated implementation space on focal plane.First spatial light modulator 4_1 and second space photomodulator 4_2 loads the random number that in electrical units II, first randomizer 10_1 and second randomizer 10_2 generates respectively, random optical modulation is carried out to the pole low light level, the former function as previously mentioned, the latter makes its emergent light with the receive direction of necessarily random probability towards single photon point probe 11, according to compressive sensing theory, its randomness is higher, and spatial discrimination precision is higher.Assemble light absorbing part part 7 (comprising optical filter and attenuator) and adopt special filter plate filtering parasitic light, the combination of many group attenuators need be adopted optical attenuation is carried out when light ratio is stronger, to prevent single photon point probe 11 saturated, then the light after light splitting is all collected in optical fiber, be transferred on single photon point probe 11, certainly also can adopt Free-space coupling.

Step 2), detect single photon and counting step.

Single photon point probe 11 detects each single photon point of object under test, exports after converting the light signal collected to effective impulse signal; Also be not able to do in time in the time interval of change at object under test, first keep the first spatial light modulator 4_1 constant, second space photomodulator 4_2 overturns repeatedly at random, counter 12 record reaches the number of the single photon point on single photon spot detector 11, after completing one group of measurement, first spatial light modulator 4_1 is turned to next frame more at random, it can be used as measured value;

Step 3), the step of compressed sensing.

The random base one_to_one corresponding that the number of the single photon point that counter 12 records and randomizer 10_2 generate, be packaged in packet memory 16 together, finally import in compressed sensing module 17, in this module, realize band signal reconstruction, recover the image in this time interval.

Step 4), after object under test changes in the time interval also not occurring once to change, repeat aforesaid operations, just can realize the time resolution of long-term sequence process of change non-periodic.

2, there is the transient process of mechanical periodicity characteristic

Fluorescence lifetime etc. is had to the transient process of mechanical periodicity characteristic, for breaking through the bottleneck of its time resolving accuracy, the present invention is based on aforesaid hypersensitive Time-resolved imaging spectrometer, propose three kinds of brand-new time discrimination measurement methods based on compressed sensing principle: 1. based on the Time-resolved imaging method of time interval measurement, 2. based on the Time-resolved imaging method of delay measurements, 3. based on the Time-resolved imaging method of photon time of arrival, consider the time resolution precision of psec, thus perfect the transient process of cycle in 80ns ~ 5ms scope can be contained, and quantitative test can be carried out with more intuitive photon number.

1., when the cycle of transient process is 1.5ms ~ 5ms, the Time-resolved imaging method based on time interval measurement can be adopted.As shown in Figure 5, the performing step of the method is as follows:

Step 1), suppose that the transient state cycle is T, is divided into d the time interval this time cycle, is denoted as t ₁, t ₂, t ₃..., t _d, in this cycle T, keep the first spatial light modulator 4_1 and second space photomodulator 4_2 all to fix a frame constant.

Step 2), the step of single-photon incident.

This step is identical with the correlation step in the long-term sequence situation that non-periodic changes, and does not repeat herein.

Step 3), detect single photon and counting step.

Single photon point probe 11 is to dropping on t _isingle photon in the time interval detects, the monochromatic light subnumber in every period of time interval recorded by counter 12, the timing code (stamp) recorded with split-second precision measuring instrument 13 is combined as a packet, so just, the time interval corresponding to each counting can be learnt, before upper once laser pulse is launched (when namely d the time interval has just all surveyed), micro mirror array instant reverse in spatial light modulator 4_2 is to next frame, and spatial light modulator 4_1 still keeps original state, repetition like this P operation equally, each t _ithe time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, then judge whether the upset frame number of micro mirror array in spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 4), otherwise in spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-executes step 1); O wherein represents complexity, and K is the degree of rarefication of imaging on spatial light modulator 4_1, and N is the pixel size of imaging on spatial light modulator 4_1.

Step 4), the step of compressed sensing.

According to step 3) result that obtains, respectively algorithm is done to this d time interval and rebuild, just can be finally inversed by the spectral intensity change procedure in the transient state cycle, i.e. time resolved spectroscopy intensity map.If the light intensity of detection light is extremely weak, then through the repeatedly cumulative meter of time segment statistics (result of time segment statistics accumulated counts as shown in Figure 6) of multiple transient state cycle, corresponding counting is made to become large.Again using the intensity of wavelength corresponding to each moment spectrum as measured value, again import compressed sensing algoritic module 17 to calculate together with the stochastic matrix generated in the first randomizer 10_1, obtain the two dimensional image under this wavelength of this moment, and then obtain Time-resolved imaging spectrum.

2. when the cycle of transient process is 80ns ~ 1.5ms, can adopt the Time-resolved imaging method based on delay measurements, when adopting the method, described hypersensitive Time-resolved imaging spectrometer need comprise digital delay 14.

Consider the dead time of single photon point probe 11 and the cycle length of nanosecond order, only can do in each transient state cycle and once effectively detect, can first through digital delay 14 before control signal arrives single photon point probe 11 and split-second precision measuring instrument 13, to complete the picosecond gate to single photon point probe 11.As shown in Figure 7, the specific implementation step based on the Time-resolved imaging method of delay measurements is as follows:

Step 1), first to keep the first spatial light modulator 4_1 and second space photomodulator 4_2 all to fix a frame constant, keep the initiating terminal of the gate-width of single photon point probe 11 to overlap with transient state period start time, gate-width is less than transient state cycle T.

Step 2), the cycle is when starting, single-photon incident.

Step 3), single photon point probe 11 and split-second precision measuring instrument 13 start to measure simultaneously, only detect once within this transient state cycle, measured count value is gate-width and the monochromatic light subnumber in this overlapping time period in transient state cycle, repeat Q time successively, then Corpus--based Method principle each counting is added and, utilize digital delay 14 that gate-width is increased 20ps after this, according to above-mentioned steps can obtain equally a counting add and, to add and as with reference to value using first, second add and with first add and difference as the statistical counting in that gate-width period extended, method just can obtain the d section statistical counting between the reference point moment to transient state end cycle moment according to this,

Step 4) if keep gate-width constant, but the due in of gate-width in advance, according to step 3) described in a series of count difference values of obtaining of operation be d section statistical counting between start time in transient state cycle to reference point moment.

Step 5), according to step 3) d section statistical counting between reference point moment to transient state end cycle moment of obtaining and step 4) d section statistical counting between start time in transient state cycle to reference point moment of obtaining, obtain the segmentation statistical counting (result of segmentation statistical counting is as shown in Figure 8) in the whole transient state cycle.

Step 6), micro mirror array instant reverse in spatial light modulator 4_2 is to next frame, and spatial light modulator 4_1 still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, after aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 7), otherwise, in spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-execute step 1), O wherein represents complexity, and K is the degree of rarefication of imaging on spatial light modulator 4_1, and N is the pixel size of imaging on spatial light modulator 4_1.

Step 7), the step of compressed sensing.

According to step 6) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, just can be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.

3. based on the Time-resolved imaging method of photon time of arrival, the method time precision is higher, and equal Fang Kuanke reaches 5ps, and be not limited to cycle length, applicability is wider.The specific implementation step of the method is as follows:

Step 1), the time to amplitude converter reference pulse be supplied in split-second precision measuring instrument 13, then the first spatial light modulator 4_1 and second space photomodulator 4_2 is kept all to fix a frame constant, utilize described time to amplitude converter that the time (start to stop) obtaining photon is recorded in the form of voltage, be recorded in corresponding time channel, and reach the time by photon number segmentation division by photon, count the d section stored counts in one-period in each time interval.

Step 2), micro mirror array instant reverse in second space photomodulator 4_2 is to next frame, and spatial light modulator 4_1 still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, respectively a corresponding P stochastic matrix.After aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in spatial light modulator 4_1 reaches O (Klog (N/K)), if reach, then perform step 3), otherwise, in spatial light modulator 4_1, micro mirror array instant reverse is to next frame, re-executes step 1); O wherein represents complexity, and K is the degree of rarefication of imaging on spatial light modulator 4_1, and N is the pixel size of imaging on spatial light modulator 4_1.

Step 3), the step of compressed sensing.

According to step 2) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, just can be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.If the light intensity of detection light is extremely weak, then add up through multiple transient state cycle repetitive measurement, make corresponding counting become large, thus obtain Time-resolved imaging spectrum.

As the preferred implementation of one, in another embodiment, before each method above-mentioned is implemented, also comprise the step that the wavelength corresponding to each pixel in Digital Micromirror Device (DMD) diagonal in second space photomodulator 4_2 is demarcated.At timing signal, the laser instrument of general selected several specific wavelength, each monochromatic light projects certain point specific on Digital Micromirror Device (DMD) diagonal line after grating beam splitting parts 6, identify this point to should specific wavelength, repeated multiple timesly obtain many measurement points, spectral distribution between adjacent two points does linear partition, thus completes the demarcation to wavelength corresponding to each pixel on whole diagonal line.By this proving operation, contribute to improving the accuracy of measuring.

Now, be aware of wavelength corresponding to each pixel on diagonal line, as shown in Figure 4, can think CCD passage on diagonal line in the similar conventional spectrometers of each pixel, spectrum is beaten in the above, certain light distribution will be had, along with seasonal effect in time series continuity, if the indexs such as the concentration of object of observation change, the light distribution fallen on the various channels also can change in time, there is respective Intensity Fluctuation, the passage of certain specific wavelength corresponding can be selected to carry out Intensity Fluctuation analysis, also can several passage comparative analysis.

As the preferred implementation of one, In yet another embodiment, before each method above-mentioned is implemented, also include the operation improving instrument signal to noise ratio (signal to noise ratio is called for short SNR).SNR is signal and the ratio of the variance of noise of instrument, and wherein noise of instrument comprises neighbourhood noise, optical noise, electrical noise (containing dark counting) etc., and variance can be regarded as the fluctuation situation of signal.If the fluctuation of signal has been flooded in the fluctuation of noise of instrument, then compressed sensing algorithm had lost efficacy; If the fluctuation of noise of instrument is less than or much smaller than the fluctuation of signal, then can almost ideal reconstruction image.Improve instrument signal to noise ratio to contribute to improving image quality.The mode improving instrument signal to noise ratio has multiple, as carried out enclosed package to instrument, improves relevant parameter and the stability of instrument of single photon point probe 11.

It should be noted last that, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted.Although with reference to embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, modify to technical scheme of the present invention or equivalent replacement, do not depart from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.

Claims (24)

1. a hypersensitive Time-resolved imaging spectrometer, it is characterized in that, comprise optical unit (I) and electrical units (II), wherein, described optical unit (I) comprises entrance slit (1), light beam-expanding collimation parts (2), optical imagery parts (3), the first spatial light modulator (4_1), concave mirror (5), grating beam splitting parts (6), second space photomodulator (4_2), assembles light absorbing part part (7); Described electrical units (II) comprises the first randomizer (10_1), the second randomizer (10_2), single photon point probe (11), counter (12), time measuring instrument (13), control module (15), packet memory (16) and compressed sensing module (17);

Other pole to be measured low light level of single-photon-level is incident by described entrance slit (1), then after the expanding and collimate of described smooth beam-expanding collimation parts (2), become directional light, this directional light is imaged on described first spatial light modulator (4_1) through described optical imagery parts (3) again; Described first spatial light modulator (4_1) does Stochastic Modulation to picture thereon, and its emergent light is reflected to described concave mirror (5) with certain random chance; Described concave mirror (5) is by reflected incident light and collimate, and makes it again to become directional light, beats to described grating beam splitting parts (6); Described grating beam splitting parts (6) form spectrum field, and second space photomodulator (4_2) on the focal plane being positioned at described grating beam splitting parts (6) forms band; Described second space photomodulator (4_2) does Stochastic Modulation to band thereon, and emergent light is reflected to described convergence light absorbing part part (7) with necessarily random probability; Described convergence light absorbing part part (7) filtering parasitic light, by the pole to be measured poor optical transmission after filtration to the single photon point probe (11) in electrical units (II);

Described first randomizer (10_1), the second randomizer (10_2) generate random number respectively and are supplied to described first spatial light modulator (4_1) and second space photomodulator (4_2) respectively, in each spatial light modulator, the random number of the total length in pixels in region forms a corresponding random base, and described first spatial light modulator (4_1) and second space photomodulator (4_2) realize Stochastic Modulation according to respective random base; Described single photon point probe (11) detects each single photon point in the low light level of pole to be measured, exports after converting the light signal collected to effective impulse signal; Described counter (12) records the number of the single photon point that described single photon point probe (11) is detected; The temporal information that described time measuring instrument (13) record photon point arrives; Described control module (15) is carried out control to whole hypersensitive Time-resolved imaging spectrometer and is coordinated, comprise and the enable of each parts and trigger pulse are controlled, guarantee counter (12), the first spatial light modulator (4_1), step coordination between second space photomodulator (4_2) and time measuring instrument (13); Two groups of random bases that the temporal information that the number of the single photon point that described counter (12) records, time measuring instrument (13) record and the first randomizer (10_1), the second randomizer (10_2) generate are together stored in described packet memory (16), finally import in described compressed sensing module (17), calculate through twice compressed sensing in this module, realize band signal reconstruction, export the Time-resolved imaging spectrum containing five-dimensional information.

2. hypersensitive Time-resolved imaging spectrometer according to claim 1, is characterized in that, described optical unit (I) also comprises catoptron (8) and exit slit (9); Described catoptron (8) is positioned between described grating beam splitting parts (6) and the light path of described second space photomodulator (4_2), for by spectral reflectance to exit slit (9).

3. hypersensitive Time-resolved imaging spectrometer according to claim 1 and 2, it is characterized in that, described electrical units (II) also comprises digital delay (14), described digital delay (14), under the control of described control module (15), completes the picosecond gate to described single photon point probe (11).

4. hypersensitive Time-resolved imaging spectrometer according to claim 1 and 2, it is characterized in that, the described Time-resolved imaging spectrum containing five-dimensional information comprise following any one or multiple: spectral intensity curve (λ, I), time resolved spectroscopy intensity map (λ, I, t), hypersensitive two-dimensional imaging (x, y), hypersensitive three-dimensional imaging (x, y, z), hypersensitive two-dimensional imaging spectrum (x, y, λ), hypersensitive time resolution two-dimensional imaging (x, y, t), hypersensitive three-dimensional imaging spectrum (x, y, z, λ), hypersensitive time resolution three-dimensional imaging (x, y, z, t), hypersensitive time resolution two-dimensional imaging spectrum (x, y, λ, t) with hypersensitive time resolution three-dimensional imaging spectrum (x, y, z, λ, t), wherein, I represents light intensity, and λ represents wavelength, and x, y, z representation space three-dimensional coordinate, t represents the time.

5. hypersensitive Time-resolved imaging spectrometer according to claim 3, it is characterized in that, the described Time-resolved imaging spectrum containing five-dimensional information comprise following any one or multiple: spectral intensity curve (λ, I), time resolved spectroscopy intensity map (λ, I, t), hypersensitive two-dimensional imaging (x, y), hypersensitive three-dimensional imaging (x, y, z), hypersensitive two-dimensional imaging spectrum (x, y, λ), hypersensitive time resolution two-dimensional imaging (x, y, t), hypersensitive three-dimensional imaging spectrum (x, y, z, λ), hypersensitive time resolution three-dimensional imaging (x, y, z, t), hypersensitive time resolution two-dimensional imaging spectrum (x, y, λ, t) with hypersensitive time resolution three-dimensional imaging spectrum (x, y, z, λ, t), wherein, I represents light intensity, and λ represents wavelength, and x, y, z representation space three-dimensional coordinate, t represents the time.

6. hypersensitive Time-resolved imaging spectrometer according to claim 1 and 2, it is characterized in that, the light field of different wave length projects the diverse location of described second space photomodulator (4_2) from being short to length by wavelength by described grating beam splitting parts (6) successively.

7. hypersensitive Time-resolved imaging spectrometer according to claim 3, it is characterized in that, the light field of different wave length projects the diverse location of described second space photomodulator (4_2) from being short to length by wavelength by described grating beam splitting parts (6) successively.

8. hypersensitive Time-resolved imaging spectrometer according to claim 1 and 2, is characterized in that, described first spatial light modulator (4_1), second space photomodulator (4_2) adopt Digital Micromirror Device to realize.

9. hypersensitive Time-resolved imaging spectrometer according to claim 3, is characterized in that, described first spatial light modulator (4_1), second space photomodulator (4_2) adopt Digital Micromirror Device to realize.

10. hypersensitive Time-resolved imaging spectrometer according to claim 8, is characterized in that, using the image space of the diagonal line of described Digital Micromirror Device as described band.

11. hypersensitive Time-resolved imaging spectrometers according to claim 1 and 2, is characterized in that, described convergence light absorbing part part (7) comprises optical filter and attenuator.

12. hypersensitive Time-resolved imaging spectrometers according to claim 3, is characterized in that, described convergence light absorbing part part (7) comprises optical filter and attenuator.

13. hypersensitive Time-resolved imaging spectrometers according to claim 1 and 2, is characterized in that, described single photon point probe (11) adopts Geiger mode avalanche diode or photomultiplier to realize.

14. hypersensitive Time-resolved imaging spectrometers according to claim 3, is characterized in that, described single photon point probe (11) adopts Geiger mode avalanche diode or photomultiplier to realize.

15. hypersensitive Time-resolved imaging spectrometers according to claim 1 and 2, is characterized in that, described time measuring instrument (13) employing is with the time correlation numbered card of time to amplitude converter function or independently time to amplitude converter realization.

16. hypersensitive Time-resolved imaging spectrometers according to claim 3, is characterized in that, described time measuring instrument (13) employing is with the time correlation numbered card of time to amplitude converter function or independently time to amplitude converter realization.

17. hypersensitive Time-resolved imaging spectrometers according to claim 1 and 2, it is characterized in that, described control module (15) guarantees counter (12), first spatial light modulator (4_1), step between second space photomodulator (4_2) and time measuring instrument (13) is coordinated to comprise: first keep described first spatial light modulator (4_1) constant, described second space photomodulator (4_2) overturns at random, micro mirror array in described second space photomodulator (4_2) often overturns once, all photons that described counter (12) stored counts detected in interval in this flip-flop transition, after having overturn, counter (12) resets, after described second space photomodulator (4_2) completes one group of measurement, described first spatial light modulator (4_1) is turned to next frame more at random, repeat aforesaid operations, until the frame number that described first spatial light modulator (4_1) overturns reaches requirement.

18. hypersensitive Time-resolved imaging spectrometers according to claim 3, it is characterized in that, described control module (15) guarantees counter (12), first spatial light modulator (4_1), step between second space photomodulator (4_2) and time measuring instrument (13) is coordinated to comprise: first keep described first spatial light modulator (4_1) constant, described second space photomodulator (4_2) overturns at random, micro mirror array in described second space photomodulator (4_2) often overturns once, all photons that described counter (12) stored counts detected in interval in this flip-flop transition, after having overturn, counter (12) resets, after described second space photomodulator (4_2) completes one group of measurement, described first spatial light modulator (4_1) is turned to next frame more at random, repeat aforesaid operations, until the frame number that described first spatial light modulator (4_1) overturns reaches requirement.

19. hypersensitive Time-resolved imaging spectrometers according to claim 1 and 2, it is characterized in that, described compressed sensing module (17) adopt in following algorithm any one realize compressed sensing: greedy reconstruction algorithm, Matching pursuitalgorithm MP, orthogonal Matching pursuitalgorithm OMP, base track algorithm BP, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm.

20. hypersensitive Time-resolved imaging spectrometers according to claim 3, it is characterized in that, described compressed sensing module (17) adopt in following algorithm any one realize compressed sensing: greedy reconstruction algorithm, Matching pursuitalgorithm MP, orthogonal Matching pursuitalgorithm OMP, base track algorithm BP, LASSO, LARS, GPSR, Bayesian Estimation algorithm, magic, IST, TV, StOMP, CoSaMP, LBI, SP, l1_ls, smp algorithm, SpaRSA algorithm, TwIST algorithm, l ₀reconstruction algorithm, l ₁reconstruction algorithm, l ₂reconstruction algorithm.

21. 1 kinds of Time-resolved imaging methods based on the hypersensitive Time-resolved imaging spectrometer one of claim 1-3 Suo Shu, for realizing the time resolution of the long-term sequence to change non-periodic, comprising:

Step 1), the step of single-photon incident;

Other pole to be measured low light level of single-photon-level is incident by described entrance slit (1), then after the expanding and collimate of described smooth beam-expanding collimation parts (2), become directional light, this directional light is imaged on described first spatial light modulator (4_1) through described optical imagery parts (3) again; Described first spatial light modulator (4_1) does Stochastic Modulation to picture thereon, and its emergent light is reflected to described concave mirror (5) with certain random chance; Described concave mirror (5) is by reflected incident light and collimate, and makes it again to become directional light, beats to described grating beam splitting parts (6); Described grating beam splitting parts (6) form spectrum field, and second space photomodulator (4_2) on the focal plane being positioned at described grating beam splitting parts (6) forms band; Described second space photomodulator (4_2) does Stochastic Modulation to band thereon, and emergent light is reflected to described convergence light absorbing part part (7) with necessarily random probability; Described convergence light absorbing part part (7) filtering parasitic light, by the pole to be measured poor optical transmission after filtration to the single photon point probe (11) in electrical units (II);

Step 2), detect single photon and counting step;

Each single photon point of single photon point probe (11) detection object under test, exports after converting the light signal collected to effective impulse signal; Also be not able to do in time in the time interval of change at the pole to be measured low light level, first keep described first spatial light modulator (4_1) constant, described second space photomodulator (4_2) overturns repeatedly at random, counter (12) record reaches the number of the single photon point on described single photon spot detector (11), after completing one group of measurement, described first spatial light modulator (4_1) is turned to next frame more at random, it can be used as measured value;

Step 3), the step of compressed sensing;

The random base one_to_one corresponding that the number of the single photon point that described counter (12) records and described second randomizer (10_2) generate, be packaged in described packet memory (16) together, finally import in described compressed sensing module (17), in this module, realize band signal reconstruction, recover the image in this time interval;

Step 4), after object under test changes in the time interval also not occurring once to change, repeat aforesaid operations, realize the time resolution of long-term sequence process of change non-periodic.

22. 1 kinds of Time-resolved imaging methods based on time interval measurement realized based on the hypersensitive Time-resolved imaging spectrometer one of claim 1-3 Suo Shu, for being that the transient process of 1.5ms ~ 5ms carries out time resolution to the cycle; Comprise:

Step 1), suppose that the transient state cycle is T, is divided into d the time interval this time cycle, is denoted as t ₁, t ₂, t ₃..., t _d, in this cycle T, keep described first spatial light modulator (4_1) and second space photomodulator (4_2) all to fix a frame constant;

Step 2), the step of single-photon incident;

Step 3), detect single photon and counting step;

Described single photon point probe (11) is to dropping on t _isingle photon in the time interval detects, the monochromatic light subnumber in every period of time interval recorded by described counter (12), the timing code recorded with described time measuring instrument (13) is combined as a packet, before upper once laser pulse is launched, micro mirror array instant reverse in described second space photomodulator (4_2) is to next frame, and described first spatial light modulator (4_1) still keeps original state, repetition like this P operation equally, each t _ithe time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, then judge whether the upset frame number of micro mirror array in described first spatial light modulator (4_1) reaches O (Klog (NK)), if reach, then perform step 4), otherwise in described first spatial light modulator (4_1), micro mirror array instant reverse is to next frame, re-executes step 1); K is wherein the degree of rarefication of the upper imaging of the first spatial light modulator (4_1), and N is the pixel size of the upper imaging of the first spatial light modulator (4_1);

Step 4), the step of compressed sensing;

According to step 3) result that obtains, do algorithm to d the time interval respectively to rebuild, be finally inversed by the spectral intensity change procedure in the transient state cycle, obtain time resolved spectroscopy intensity map, again using the intensity of wavelength corresponding to each moment spectrum as measured value, again import compressed sensing module (17) to calculate together with the stochastic matrix generated in described first randomizer (10_1), obtain the two dimensional image under this wavelength of this moment, and then obtain Time-resolved imaging spectrum.

23. 1 kinds of Time-resolved imaging methods based on delay measurements realized based on hypersensitive Time-resolved imaging spectrometer according to claim 3, for being that the transient process of 80ns ~ 1.5ms carries out time resolution to the cycle; The method comprises:

Step 1), first to keep described first spatial light modulator (4_1) and second space photomodulator (4_2) all to fix a frame constant, keep the initiating terminal of the gate-width of single photon point probe (11) to overlap with transient state period start time, gate-width is less than transient state cycle T;

Step 2), the cycle is when starting, single-photon incident;

Step 3), described single photon point probe (11) and time measuring instrument (13) start to measure simultaneously, only detect once within this transient state cycle, measured count value is gate-width and the monochromatic light subnumber in this overlapping time period in transient state cycle, successively repeat Q time, then Corpus--based Method principle each counting is added with;

Step 4), utilize described digital delay (14) that gate-width is increased 20ps, re-execute step 3) obtain another counting add and, to add and as with reference to value using first, second add and with first add and difference as the statistical counting in that gate-width period extended, obtain the d section statistical counting between the reference point moment to transient state end cycle moment;

Step 5), keep gate-width constant, in advance the due in of gate-width, re-executes step 3) with step 4), using a series of count difference values of obtaining as start time in transient state cycle to the reference point moment between d section statistical counting;

Step 6), according to step 4) d section statistical counting between reference point moment to transient state end cycle moment of obtaining and step 5) d section statistical counting between start time in transient state cycle to reference point moment of obtaining, obtain the segmentation statistical counting in the whole transient state cycle;

Step 7), micro mirror array instant reverse in described second space photomodulator (4_2) is to next frame, and the first spatial light modulator (4_1) still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, a corresponding P stochastic matrix respectively, after aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in described first spatial light modulator (4_1) reaches O (Klog (NK)), if reach, then perform step 8), otherwise, in first spatial light modulator (4_1), micro mirror array instant reverse is to next frame, re-execute step 1), K is wherein the degree of rarefication of the upper imaging of the first spatial light modulator (4_1), and N is the pixel size of the upper imaging of the first spatial light modulator (4_1),

Step 8), the step of compressed sensing;

According to step 7) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.

24. 1 kinds of Time-resolved imaging methods based on photon time of arrival realized based on the hypersensitive Time-resolved imaging spectrometer one of claim 1-3 Suo Shu, comprising:

Step 1), the time to amplitude converter reference pulse be supplied in described time measuring instrument (13), then described first spatial light modulator (4_1) and second space photomodulator (4_2) is kept all to fix a frame constant, utilize described time to amplitude converter that the time obtaining photon is recorded in the form of voltage, be recorded in corresponding time channel, and reach the time by photon number segmentation division by photon, count the d section stored counts in one-period in each time interval;

Step 2), micro mirror array instant reverse in described second space photomodulator (4_2) is to next frame, and the first spatial light modulator (4_1) still keeps original state, repetition like this P operation equally, each time interval just should have P counting mutually, respectively a corresponding P stochastic matrix; After aforesaid operations terminates, then judge whether the upset frame number of micro mirror array in the first spatial light modulator (4_1) reaches O (Klog (NK)), if reach, then perform step 3), otherwise, in first spatial light modulator (4_1), micro mirror array instant reverse is to next frame, re-executes step 1); K is wherein the degree of rarefication of the upper imaging of the first spatial light modulator (4_1), and N is the pixel size of the upper imaging of the first spatial light modulator (4_1);

Step 3), the step of compressed sensing;

According to step 2) result that obtains, respectively algorithm is done to this d time interval and rebuild, then secondary algorithm is done to the spectral intensity of each wavelength of each moment rebuild, be finally inversed by the Time-resolved imaging spectrum in the transient state cycle.