CN107632402A - A kind of continuous/ultrafast micro imaging method of the mould of burst/difference three for real-time monitored micro-nano transient phenomena - Google Patents

Abstract

The invention discloses a continuous/burst/phase-difference three-mode ultrafast microscopic imaging method for real-time observation of micro-nano transient phenomena. Specifically, it provides an optical path conversion module that changes the laser direction and converts the same ultrafast pulse laser The output femtosecond laser passes through the optical path conversion module and enters continuous imaging or burst imaging for imaging processing. When observing the same micro-nano transient phenomenon, it can not only continuously capture the fast dynamic characteristics in the micro-nano environment, but also obtain several frames of imaging with a time resolution of femtosecond level at important moments of the experiment. By adding a phase detection module, in the same transient phenomenon, both the transparent part of the sample and the opaque part of the sample can be observed.

Description

A continuous/burst/phase-difference three-mode ultrafast for real-time observation of micro-nano transients Microscopic imaging method

technical field

The invention relates to an ultrafast imaging technology, in particular to a continuous/burst/phase difference three-mode ultrafast microscopic imaging method for real-time observation of micro-nano transient phenomena.

Background technique

Traditional CCD and CMOS imaging are the most widely used imaging technologies. CCD and CMOS cannot clearly and sensitively capture the dynamic occurrence of ultrafast processes, especially for imaging objects at the micro-nano scale. Even if dynamic phenomena are slow, high temporal resolution is required at the micro- and nanoscale.

A common problem with optical imaging is that the higher the frame rate, the fewer photons are collected per frame. In order to obtain a higher time resolution, the commonly used method is to reduce the spatial resolution and use a high-power light source, but this is not an ideal solution, not only will it generate optical noise, but also when performing micro-nano scale imaging, the light will be concentrated In very small areas, the observed object may be damaged.

In occasions where transient phenomena need to be observed, such as studying photochemistry, phononics, plasma physics, and fast dynamic properties of proteins in living cells, the observation requires not only continuous imaging on the order of nanoseconds (10 ^-9 s), but also Burst imaging with several frames of femtosecond (10 ^-15 s) time resolution is required in order to continuously take pictures at ultra-short time intervals at critical moments in the research process. However, the current continuous imaging technology can only reach the nanosecond level, and if the experimental observation needs to reach the femtosecond level imaging at a certain moment, the pump detection technology and ultrafast burst imaging technology are used. In the occasions where transient phenomena need to be observed, in order to observe the fast dynamic characteristics of matter, both ultrafast continuous imaging and ultrafast burst imaging are required.

Furthermore, when the observed object is highly transparent for a certain period of time, the vibration after the light wave passes through is basically unchanged, and only the phase changes. The human eye can only distinguish the wavelength and amplitude of visible light, but cannot distinguish the change of phase. Therefore, when the same observed object appears transparent and opaque at different time periods, only ultrafast imaging technology or phase contrast microscopy technology can no longer meet the observation requirements.

Contents of the invention

The purpose of the present invention is to provide a continuous/burst/phase difference three-mode ultra-fast microscopic imaging method for real-time observation of micro-nano transient phenomena, which can continuously capture the micro-nano environment Under the fast dynamic characteristics, and at the important moment of the experiment, several frames of imaging with time resolution of femtosecond level can be obtained.

In order to achieve the above purpose, the continuous/burst/phase difference three-mode ultrafast microscopic imaging method for real-time observation of micro-nano transient phenomena involved in the present invention is special in that it provides an optical path conversion module that changes the laser Direction, the femtosecond laser output from the same ultrafast pulse laser passes through the optical path conversion module and then enters continuous imaging or burst imaging for imaging processing. The image processing systems for continuous imaging and burst imaging both include phase detection modules. It is used to detect the transparent part of the analyte.

Further, the optical path conversion module includes a plurality of flip mirrors.

Furthermore, the optical path conversion module includes a first flip mirror, a second flip mirror and a mirror, and the optical path conversion module is compatible with the ultrafast continuous imaging pulse spatial dispersion module for continuous imaging and the ultrafast burst imaging for burst imaging Together, the pulse time domain shaping modules form an integrated dual-mode pulse shaping module, in which:

The first flip mirror is used to change the femtosecond laser path, so as to enter the ultrafast continuous imaging pulse space dispersion module or the ultrafast burst imaging pulse time domain shaping module;

The mirror is used to change the output laser of the ultrafast continuous imaging pulse spatial dispersion module, so that it acts on the second flip mirror;

The second inverting mirror is used to change the path of the laser converted by the mirror or the output laser of the ultrafast burst imaging pulse time domain shaping module to the subsequent operation of continuous imaging or burst imaging.

Still further, the output end of the dual-mode pulse shaping module is also provided with a third flip mirror, and the third flip mirror changes the output laser light of the dual-mode pulse shaping module to the subsequent operation of continuous imaging or burst imaging.

The advantages of the present invention are:

1. This imaging method uses common optical instruments, which is easy to realize.

2. When observing the same micro-nano transient phenomenon, it can not only continuously capture the fast dynamic characteristics in the micro-nano environment, but also obtain several frames of imaging with a time resolution of femtosecond level at important moments of the experiment. Make full use of the time-frequency characteristics of ultrafast femtosecond pulses to realize dual-mode imaging that can flexibly switch imaging methods. According to application requirements, the ultrafast process can be continuously detected in the whole process or key detection at specific time points, and the detection method can be switched in real time. . The organic combination of various individual detection methods provides a new one-stop solution for fine processing process detection.

3. Adding a phase detection module, in the same transient phenomenon, both the transparent part of the sample and the opaque part of the sample can be observed.

Description of drawings

Fig. 1 is the structural representation of an embodiment of the patent of the present invention;

Fig. 2 is the schematic diagram of the pulse shaping module in the structural schematic diagram;

3 is a schematic diagram of an ultrafast continuous imaging pulse spatial dispersion module;

4 is a schematic diagram of an ultrafast burst imaging pulse time-domain shaping module;

Fig. 5 is a structural schematic diagram of an intermediate frequency-time conversion and optical amplification module;

Fig. 6 is a schematic diagram of continuous/burst/phase contrast three-mode ultrafast microscopic imaging.

In the figure: 101: ultrafast pulse laser; 102: ultrafast continuous imaging pulse anti-spatial dispersion module; 103: optical path collimator; 104: dual-mode pulse shaping module; 105: third flip mirror; 106: optical path collimator ;107: convex lens; 108: observation object; 109: frequency-time conversion and optical amplification module; 110: single-pixel photodiode; 111: mirror; 112: scattering grating; 113: collimating grating; pulse; 115: image processing system.

201: femtosecond pulse; 202: first flip mirror; 203: ultrafast continuous imaging pulse spatial dispersion module; 204: ultrafast burst imaging pulse time domain shaping module; 205: mirror; 206: second flip mirror.

301: collimator; 302: convex lens; 303: convex lens; 304: cylindrical mirror; 305: virtual image phase array; 306: diffraction grating.

401: pulse stretcher; 402: laser pulse after stretching; 403: broadband mirror; 404: grating; 405: lens; 406: spatial light modulator; 407: lens; 408: grating; 409: broadband mirror; 410: multiple sub-pulses after time-domain shaping.

501: Erbium-doped fiber amplifier; 502: Raman pump; 503: wavelength division multiplexer; 504: dispersion compensation fiber; 505: wavelength division multiplexer; 506: Raman pump.

detailed description

Below in conjunction with accompanying drawing and specific implementation the present invention will be described in further detail:

The continuous/burst/phase difference three-mode ultrafast microscopic imaging method designed by the present invention for real-time observation of micro-nano transient phenomena is specifically: providing an optical path conversion module, changing the direction of the laser, and using the same ultrafast pulse laser The output femtosecond laser passes through the optical path conversion module and then enters continuous imaging or burst imaging for imaging processing. The image processing systems for continuous imaging and burst imaging both include a phase detection module for detecting the transparent part of the object to be measured .

Wherein, the optical path conversion module includes a plurality of flip mirrors. In this embodiment, the optical path conversion module includes a first flip mirror, a second flip mirror and a mirror, and the optical path conversion module is connected with the ultrafast continuous imaging pulse spatial dispersion module for continuous imaging and the ultrafast burst imaging pulse time domain shaping for burst imaging Together, the modules form an integrated dual-mode pulse shaping module where:

The first flip mirror is used to change the femtosecond laser path, so as to enter the ultrafast continuous imaging pulse space dispersion module or the ultrafast burst imaging pulse time domain shaping module;

The mirror is used to change the output laser of the ultrafast continuous imaging pulse spatial dispersion module, so that it acts on the second flip mirror;

The second inverting mirror is used to change the path of the laser converted by the mirror or the output laser of the ultrafast burst imaging pulse time domain shaping module to the subsequent operation of continuous imaging or burst imaging.

To facilitate the arrangement of subsequent operations, the output end of the dual-mode pulse shaping module is also provided with a third inverting mirror, which changes the output laser of the dual-mode pulse shaping module to subsequent operations of continuous imaging or burst imaging.

Concrete realization process of the present invention is as follows:

As shown in the accompanying drawings, the three-mode ultrafast microscopic imaging method of the present invention includes an optical path a and an optical path b. The optical path a and the optical path b represent continuous imaging and burst imaging respectively. 206 for switching. Specifically: when the first reversing mirror 202 and the second reversing mirror 206 are turned to the horizontal position, it is the optical path a; when the first reversing mirror 202 and the second reversing mirror 206 are turned to 45 degrees, it is the optical path b.

The direction of its optical path a is as follows: firstly, the ultrafast pulse laser 101 is used to output femtosecond laser; then, it enters the ultrafast continuous imaging pulse spatial dispersion module 203 in the dual-mode pulse shaping module 104 through the collimator 103, from the collimator 301 to the The ultrashort pulse adjusts the size of the spot through the lens group (302, 303), and enters the dispersion unit composed of the cylindrical lens 304, the virtual image phase array 305 and the diffraction grating 306, and the pulse is expanded according to the frequency in space to form a rainbow spot; then, after the first Three flipping mirrors 105 and collimator 106 lens 107, the rainbow spot converges on the sample 108; then, after diffuse reflection, the encoded pulse ultrafast continuous imaging pulse anti-spatial dispersion module 102, the rainbow spot is reduced to a short pulse, enters The frequency-time conversion and optical amplification module 109 converts the information in the frequency domain to the time domain. Since the optical signal diffusely reflected by the observed object is very weak and has a wide spectrum, band-pass filtering is performed before the frequency-time conversion, and after doping Erbium fiber amplifier 501 and distributed Raman amplification, specifically Raman pumps 502, 506, wavelength division multiplexer 503, dispersion compensating fiber 504, and wavelength division multiplexer 505; finally, the time domain information of the light beam is passed through the photoelectric The diode 110 photoelectric conversion, the phase detection module and the image processing system 115 acquire continuous imaging on the order of nanoseconds.

The direction of the optical path b is as follows: first, the ultrafast pulse laser 101 is used to output femtosecond laser; then, through the collimator 103, it enters the ultrafast burst imaging pulse time domain shaping module 204 in the dual-mode pulse shaping module 104, and the pulse 402 is reflected The mirror 403 transmits the light beam to the grating 404, the grating 404 spreads the light beam according to the frequency, the lens 405 collimates the light beam and passes through the liquid crystal phase delayer 406, and the liquid crystal phase delayer 406 performs frequency-domain Fourier transform on the light beam to perform time domain shaping. The shaped light is focused and beam-combined through the lens 407 and the grating 408 , and then through the mirror 409 to form a plurality of time-domain shaped sub-pulses 410 . The frequency spectrum of the original laser pulse 402 is divided into several segments in the frequency domain, and each band forms a sub-pulse, and the multiple sub-pulses 410 after the time-domain shaping have different time intervals; then, the multiple sub-pulses 410 after the time-domain shaping pass through the The third flip mirror 105 and the collimator 106 lens 107 converge on the sample 108, and encode the two-dimensional image information of the target surface onto these pulse spectra. Since there is a certain time interval between sub-pulses, these sub-pulses The pulse will encode information at different times in a very short period of time, providing conditions for ultrafast burst imaging; then, after diffuse reflection, the sub-pulse with different frequencies will pass through the mirror 111, the scattering grating 112 and the collimating grating 113 when returning. The spectra are uniformly arranged in space; finally, the phase detection module and the image processing system 115 are used to obtain imaging with a time resolution of femtosecond level.

The imaging method of the present invention uses common optical instruments, which is convenient for realization. When observing the same micro-nano transient phenomenon, it can not only continuously capture the fast dynamic characteristics in the micro-nano environment, but also obtain several frames of imaging with a time resolution of femtosecond level at important moments of the experiment. Make full use of the time-frequency characteristics of ultrafast femtosecond pulses to realize dual-mode imaging that can flexibly switch imaging methods. According to application requirements, the ultrafast process can be continuously detected in the whole process or key detection at specific time points, and the detection method can be switched in real time. . The organic combination of various individual detection methods provides a new one-stop solution for fine processing process detection. In the present invention, a phase detection module is added, and in the same transient phenomenon, both the transparent part of the sample and the opaque part of the sample can be observed.

Claims (4)

1. a kind of continuous/ultrafast micro imaging method of the mould of burst/difference three for real-time monitored micro-nano transient phenomena, its feature It is：A kind of light path converting module is provided, changes laser direction, the femtosecond laser that same ultrafast pulsed laser device exports is passed through Enter continuous imaging after light path converting module or burst imaging carries out imaging, wherein, continuous imaging and burst imaging Include phase detecting module in image processing system, for detecting the transparent part of determinand.

2. continuous/mould of burst/difference three according to claim 1 for real-time monitored micro-nano transient phenomena is ultrafast micro- Imaging method, it is characterised in that：The light path converting module includes multiple upset mirrors.

3. continuous/mould of burst/difference three according to claim 2 for real-time monitored micro-nano transient phenomena is ultrafast micro- Imaging method, it is characterised in that：The light path converting module includes the first upset mirror, the second upset mirror and reflective mirror, the light The ultrafast burst imaging arteries and veins of the ultrafast continuous imaging pulse interval dispersion compensation module and burst imaging of road modular converter and continuous imaging Rush time domain Shaping Module and be collectively forming integrated bimodulus shaping pulse module, wherein：

First upset mirror is used to change femtosecond laser path, hence into ultrafast continuous imaging pulse interval dispersion compensation module or super Fast burst imaging pulse time domain Shaping Module；

The reflective mirror is used for the output laser for changing ultrafast continuous imaging pulse interval dispersion compensation module, it is acted on second and turns over On tilting mirror；

The second upset mirror is used for the laser of reflective mirror conversion or ultrafast burst imaging pulse time domain Shaping Module output The path of laser changes the subsequent operation to continuous imaging or burst imaging.

4. continuous/mould of burst/difference three according to claim 3 for real-time monitored micro-nano transient phenomena is ultrafast micro- Imaging method, it is characterised in that：The bimodulus shaping pulse module output end is additionally provided with the 3rd upset mirror, the 3rd upset Mirror changes bimodulus shaping pulse module output laser the subsequent operation to continuous imaging or burst imaging.