CN202133468U - System for measuring pulse laser energy - Google Patents

Abstract

The present utility model relates to a system for measuring pulse laser energy. The system comprises an incident laser, an optical cleaving plate, a standard energy meter, an integrating sphere and a science grade CCD, the optical cleaving plate is arranged on the emitting light path of the incident laser, the standard energy meter is arranged on the reflected light path of the optical cleaving plate, the integrating sphere is arranged on the transmitted light path of the optical cleaving plate, and the sensitive surface of the science grade CCD is in the same level with the inner surface of the integrating sphere. The system for measuring pulse laser energy is high in measuring precision, simple in system and low in cost.

Description

A kind of system that is used to measure pulsed laser energy

Technical field

The utility model belongs to optical field, relates to a kind of measuring system of laser energy, relates in particular to a kind of scientific grade CCD that adopts and carries out the system that pulsed laser energy is measured.

Background technology

Laser energy is an important basic index of pulse laser; Especially to high power laser system, need the definite pulse energy of knowing its output what are, also need know the intensity distributions of laser light field simultaneously; Therefore be used for the parameter measurement assembly of high power laser light; The general energy meter and the scientific grade CCD device that carries out the light field uniformity test that all disposes energy measurement analyzed the relatively measurement essence of two types of devices, all is that the intensity of light field is measured; System design is loaded down with trivial details, and cost is high.

The utility model content

In order to solve the above-mentioned technical matters that exists in the background technology, the utility model provides that a kind of measuring accuracy is high, the system of system simplification and measurement pulsed laser energy with low cost.

The technical solution of the utility model is: the utility model provides a kind of system that is used to measure pulsed laser energy, and its special character is: the said system that is used to measure pulsed laser energy comprises that incident laser instrument, optics splits plate, standard energy meter, integrating sphere and scientific grade CCD; Said optics is split on the emitting light path of plate setting and incident laser device; Said standard energy meter is arranged at optics and splits on the reflected light path of plate; Said integrating sphere is arranged at optics and splits on the transmitted light path of plate; The sensitive area of said scientific grade CCD is concordant with the integrating sphere inside surface.

Above-mentioned integrating sphere inside surface sphere area is not less than 100 times with the ratio of the area of the sensitive area of scientific grade CCD.

What above-mentioned optics was split plate splits the angle less than 5 °.

The utility model has the advantages that:

The utility model mainly provides a kind of scientific grade CCD that adopts and carries out the system that pulsed laser energy is measured, and its objective is alternative energy meter, the two is carried out function synthesize, and the simplified system design reduces cost, and realizes a kind of new way of energy measurement.The utility model adopts a kind of energy reference transfer device, the benchmark of standard energy meter is delivered to the gray scale unit of CCD output; Adopt CCD device to carry out energy measurement through demarcating; Through specific data processing method, obtain being input to the energy value of CCD target surface, the thinking that the utility model adopts benchmark to transform is demarcated CCD; Adopt standard energy meter, integrating sphere, the optics of plated film is not split plate CCD is demarcated; The benchmark of standard energy meter accurately is delivered on the gray scale of CCD, and the linear dynamic range of CCD is demarcated, obtain the characteristic parameter of CCD photoelectric response; Analyzed output gray level---the mathematic(al) representation between the energy measurements that adopts CCD; Provide the CCD energy measurement data processing method that exists in actual use under the background noise situation, provided the precision that measurement result can reach.Do not increasing the influence of adopting data processing method background correction veiling glare under the hardware case; Above its error of CCD energy measurement method is confirmed, promptly selectes the linearity error of CCD.

Description of drawings

Fig. 1 is that the utility model energy reference-CCD gray scale is transmitted synoptic diagram;

Fig. 2 is the CCD energy measurement synoptic diagram of the utility model.

Embodiment

Referring to Fig. 1, the utility model provides a kind of system that is used to measure pulsed laser energy, and this system comprises that incident laser instrument, optics splits plate 3, standard energy meter 4, integrating sphere 1 and scientific grade CCD 2; Optics is split on the emitting light path of plate 3 settings and incident laser device; Standard energy meter 4 is arranged at optics and splits on the reflected light path of plate 3; Integrating sphere 1 is arranged at optics and splits on the transmitted light path of plate 3; The sensitive area of scientific grade CCD 2 is concordant with integrating sphere 1 inside surface.

Integrating sphere 1 inside surface sphere area is not less than 100 times with the ratio of the area of the sensitive area of scientific grade CCD 2, and what optics was split plate 3 splits the angle less than 5 °.

The system that is used to measure pulsed laser energy that the utility model provided is when carrying out work; For the gray scale of obtaining the intensity distributions of setting up the known laser light field and the transformational relation between the laser energy, this system just comprises that incident laser instrument, optics splits plate 3, standard energy meter 4, integrating sphere 1 and scientific grade CCD 2; Standard energy meter 4 is measured the energy of being exported to integrating sphere 1; Be known energy; Can directly read from scientific grade CCD 2 through the gray scale after the scientific grade CCD 2; Therefore, for known energy with can just can set up gray scale and the transformational relation between the laser energy of the intensity distributions of known laser light field from the gray scale that scientific grade CCD 2 is directly read.

When obtaining the testing laser energy, this system only comprises incident laser instrument, integrating sphere 1 and scientific grade CCD 2; After reading the gray scale of scientific grade CCD 2, just can directly obtain the testing laser energy according to the gray scale and the transformational relation between the laser energy of the intensity distributions of the known laser light field of having set up, very easy to use.

Come the utility model is specified with a preferred embodiment below:

The first step: energy reference is transmitted to the CCD gray scale:

Referring to Fig. 1, scientific grade CCD 2 adopts the Scientific Grade low-noise device that carries out the light field uniformity measurement, integrating sphere 1 inside surface sphere area and its outlet, just Scientific Grade connect the CCD2 area ratio greater than more than 100 times; Standard energy meter 4, thickness are that the optics of the not plated film of ubk7 is split the pulse laser of plate 3, incident less than 8mm, material;

Scientific grade CCD 2 must make the sensitive area of scientific grade CCD 2 concordant with the integrating sphere inside surface when being connected with integrating sphere 1, need take down the shell of scientific grade CCD 2 for this reason; Timing signal adopts the collimation laser of scientific grade CCD 2 operation wavelengths as light source input integral ball 1;

The incident laser low-angle incides optics splits the front surface of plate (angle is less than 5 °), and optics is split plate front surface reflection gloss and received with the standard energy calorimeter, and its transmitted light incides in the integrating sphere;

Suppose that incident laser energy is a unit, the beam split coefficient of splitting plate is r, and transmission coefficient is t, and the inner surface area of integrating sphere is S _s, CCD target surface area is S _c, standard energy meter reading is N, and the absorption of material is ignored (when Theoretical Calculation is illustrated in material thickness less than 10mm, to the laser absorption of operation wavelength less than 0.1%), and the energy of the then actual CCD of inciding target surface is:

For the optical surface of plated film not; Under the low-angle condition of incidence; It is unique definite that its reflectivity is pinched your formula by phenanthrene, so r confirms in the formula, and the target surface of the internal surface area of integrating sphere and CCD also is definite known; Then can obtain the energy value that the CCD target surface receives by formula, the gray scale of CCD pixel output simultaneously also is known;

Under different intakes; Obtain a series of energy---target surface gray average measurement point; Through least square method can simulate photoelectric response curve x for the input laser energy by the 4th) step obtain;

is the slope of photoelectric response;

is the background of response device; is the pixel gray average output of CCD, obtains the transitive relation that the photoelectric response curve has promptly obtained energy reference-gray scale benchmark;

Second step: the CCD carries out the realization that pulsed laser energy is measured:

Accompanying drawing 2 is light path examples of laser parameter measurement assembly, in this assembly, promptly includes the energy calorimeter, also includes the scientific grade CCD of carrying out the distribution of light intensity distribution measuring, is that the example explanation adopts scientific grade CCD to carry out the realization of energy measurement with this figure;

Suppose with energy be the laser projections of x to the CCD target surface, all there is the relational expression of photoelectric response in each CCD pixel, therefore have:

$\left\{\begin{array}{c}(y_1-b_1)=k_{1}x\\ (y_2-b_2)=k_{2}x\\ \mathrm{KK}\\ (y_n-b_n)=k_{n}x\end{array}\right.$

Following formula is carried out the energy x expression formula that the right and left summation and arrangement can obtain incident laser is:

$x=\frac{(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{b}_i)}{n\stackrel{\‾}{k}}=\frac{(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i-n\stackrel{\‾}{b})}{n\stackrel{\‾}{k}}$

Be " first step " the 5th) find the solution and obtain y _iBe the gray scale output of CCD pixel, n is the pixel number of CCD, and this relational expression is the mathematical expression that CCD carries out energy measurement;

The zone of action of the graphical representation laser in the middle of the CCD target surface is in reality, because the pump light of laser system and the residual reflection of optical surface; Inevitably there is parasitic light in the ccd image; For the output of CCD, be the comprehensive output that comprises veiling glare and signal, the intensity of supposing veiling glare is x _Assorted, signal intensity is x _Letter, then the output of CCD is x _Assorted+ x _LetterThe result, by the 3rd) step mathematic(al) representation have:

Need know the energy x of veiling glare signal _AssortedCould be by calculating x _Letter

Mechanism by veiling glare produces knows, it acts on the effect that effect on the CCD is equal to the integrating sphere effect, and the just in time real-time record of the outer CCD target surface of image region each send out " signal " of time veiling glare, therefore have:

veiling glare average gray scale for being obtained by the outer pixel statistics of image region wherein, substitution the 4th) the step relational expression gets:

Promptly obtained the energy of input laser;

Error analysis in measurement: by above relational expression know the factor that influences the energy measurement accuracy comprise

be all pixels of CCD gray scale accumulation with; And Analysis on Mechanism and experimental study show CCD pixel electrical noise accord with normal distribution characteristic; Therefore

can eliminate electronics noise effect at random, can think that this influence to energy measurement ignores;

represented the outer background " signal " of image-region equally; Its characteristic is identical with

, can think that also this influence to energy measurement ignores; What

represented is the photoelectric response slope of a curve; This value is influential to energy measurements, to the 5th) step formula both sides get differential and get:

X is removed on the following formula both sides together _Letter:

The relative error of

expression energy measurement;

promptly represented the nonlinearity of CCD device, so the error of energy measurement is represented by the nonlinearity of CCD device.

Claims (3)

1. system that is used to measure pulsed laser energy is characterized in that: the said system that is used to measure pulsed laser energy comprises that incident laser instrument, optics splits plate, standard energy meter, integrating sphere and scientific grade CCD; Said optics is split on the emitting light path of plate setting and incident laser device; Said standard energy meter is arranged at optics and splits on the reflected light path of plate; Said integrating sphere is arranged at optics and splits on the transmitted light path of plate; The sensitive area of said scientific grade CCD is concordant with the integrating sphere inside surface.

2. the system that is used to measure pulsed laser energy according to claim 1 is characterized in that: said integrating sphere inside surface sphere area is not less than 100 times with the ratio of the area of the sensitive area of scientific grade CCD.

3. the system that is used to measure pulsed laser energy according to claim 1 and 2 is characterized in that: what said optics was split plate splits the angle less than 5 °.

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