CN111999035A

CN111999035A - F-P filter transmission curve calibration method using frequency stabilization He-Ne laser

Info

Publication number: CN111999035A
Application number: CN202010793773.5A
Authority: CN
Inventors: 杨金生; 胡兴成; 饶长辉
Original assignee: Institute of Optics and Electronics of CAS
Current assignee: Institute of Optics and Electronics of CAS
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2020-11-27

Abstract

The invention discloses a calibration method for a transmission curve of an F-P filter by using a frequency stabilized He-Ne laser, which can very accurately calibrate the transmission curve of the F-P filter; the frequency stabilizing He-Ne laser with extremely narrow bandwidth is utilized to generate frequency stabilizing laser and expand beam for collimation, and the splitting ratio is 1: laser is divided into 2 beams by the spectroscope 1, one beam directly enters the second CCD, the other beam passes through the F-P filter to be calibrated and is received by the first CCD, and the response characteristic of the CCD and the splitting ratio of the spectroscope are calibrated before an experiment. The tuning position of the F-P filter is adjusted for multiple times, the laser emergent light intensity and the transmission light power corresponding to different tuning positions are measured at the same time, the measured value is corrected by utilizing the CCD response characteristic and the splitting ratio of the spectroscope, the transmittance is calculated, a Gaussian function is used for fitting to obtain a relationship curve of the transmittance and the tuning wavelength, the average value is obtained by repeated measurement for multiple times, the average value is the transmission curve of the F-P filter, and the main application parameters of the filter such as half width, peak transmittance and the like can be further calculated.

Description

F-P filter transmission curve calibration method using frequency stabilization He-Ne laser

Technical Field

The invention relates to a calibration method of a transmission curve of an F-P filter, in particular to a calibration method of a transmission curve of an F-P filter by using a frequency stabilizing He-Ne laser.

Background

The F-P filter is an excellent filter device, is mainly developed based on the multi-beam interference principle of parallel flat plates, and is widely used for astronomical observation as a scanning imaging spectrometer. Before F-P is formally applied to scanning imaging, its main performance parameters must be scaled to ensure that accurate data can be obtained during imaging.

The peak transmittance and half-width are the main application performance parameters of the F-P, and in order to calibrate it accurately, the transmission curve thereof generally needs to be measured.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a method for systematically calibrating the performance parameters of major applications of F-P filters is presented.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for calibrating the transmission curve of F-P filter by frequency stabilized He-Ne laser includes the following steps:

step 1, generating frequency stabilized laser by using a frequency stabilized He-Ne laser with extremely narrow bandwidth, expanding beam and collimating;

step 2, calibrating the response of the first CCD and the second CCD and the splitting ratio of the spectroscope without placing an F-P filter to be calibrated;

step 3, dividing the laser into 2 beams by using a spectroscope, wherein one beam directly enters a second CCD, and the other beam passes through an F-P filter to be calibrated and is received by a first CCD;

step 4, adjusting the tuning position of the F-P filter to be calibrated to a certain tuning wavelength lambda_iMeasuring the emergent light power of the laser and the transmission light power of the laser passing through the F-P filter to be calibrated at the same time;

step 5, correcting the measured value and calculating the transmittance by utilizing the response characteristics of the first CCD and the second CCD and the splitting ratio of the spectroscope;

step 6, changing lambda_iAnd repeating the

steps

4 and 5, measuring a plurality of groups of data of the transmissivity A-tuning wavelength lambda, fitting a curve by using a Gaussian function, and calculating the half width and the peak transmissivity of the curve.

Compared with the prior art, the invention has the beneficial effects that:

(1) the calibration method of the F-P filter has the advantages of simple experimental device and operation, and can accurately calibrate the transmission curve of the F-P filter.

(2) Meanwhile, the emergent light intensity of the laser and the transmission light intensity of the laser passing through the F-P filter are measured to calculate the transmittance, so that the influence of the change of the output power of the light source on the calculation of the transmittance is avoided, and the requirement on the stability of the output power of the light source is low.

Drawings

FIG. 1 is a flow chart of a method of scaling the transmission curve of an F-P filter according to the present invention;

FIG. 2 is a schematic view of a calibrated experimental apparatus;

the reference numbers in the figures mean: 1 is a frequency stabilizing He-Ne laser, 2 is a beam expanding collimating lens, 3 is a spectroscope, 4 is an F-P filter to be calibrated, 5 is a first CCD, and 6 is a second CCD.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 2, a frequency-stabilized He-Ne laser 1 generates a narrow-band frequency-stabilized laser during calibration, and after passing through a beam-expanding collimating lens 2, the narrow-band frequency-stabilized laser is divided into two paths with equal intensity by a beam splitter 3, wherein one path is directly used for measuring the optical power by a second CCD 6, and the other path penetrates through an F-P filter 4 to be calibrated and then enters a first CCD 5, and a computer controls the tuning of the F-P filter 4 to be calibrated and the image acquisition of the first CCD 5 and the second CCD 6. In order to avoid the influence of CCD response difference and spectroscopic errors of the spectroscope 3 on measurement, the response of 2 CCDs and the spectroscopic ratio of the spectroscope 3 are calibrated before the F-P filter 4 to be calibrated is calibrated. As shown in fig. 1, the specific process of calibrating the F-P filter 4 to be calibrated is as follows:

step 1, generating frequency stabilized laser by using a frequency stabilized He-Ne laser 1 with extremely narrow bandwidth, and expanding and collimating the laser by using an expanding and collimating lens 2;

step 2, the F-P filter 4 to be calibrated is not put in, and the responses of the first CCD 5 and the second CCD 6 and the splitting ratio of the spectroscope 3 are calibrated;

step 3, dividing the laser into 2 beams by using a spectroscope 3, wherein one beam directly enters a second CCD 6, and the other beam passes through an F-P filter 4 to be calibrated and is received by a first CCD 5;

step 4, adjusting the tuning position of the F-P filter 4 to be calibrated to a certain tuning wavelength lambda_iMeanwhile, the emergent light power of the laser and the transmission light power of the laser passing through the F-P filter 4 to be calibrated are measured;

step 5, correcting the measured value and calculating the transmittance by utilizing the response characteristics of the first CCD 5 and the second CCD 6 and the splitting ratio of the spectroscope 3;

step 6, changing lambda_iAnd repeating the

steps

4 and 5, measuring a plurality of groups of data of the transmissivity A-tuning wavelength lambda, fitting a curve by using a Gaussian function, and calculating the half width and the peak transmissivity of the curve. Let the fitted gaussian function curve be:

then there is a change in the number of,

A_m＝a

wherein A is a transmittance, a, b, λ₀For the fitting parameters to be calculated, A_mAnd w is the peak transmittance of the F-P filter to be calibrated, and w is the half width of the F-P filter to be calibrated.

Claims

1. A calibration method for the transmission curve of an F-P filter by using a frequency stabilized He-Ne laser is characterized by comprising the following steps:

step 6, changing lambda_iRepeating the steps 4 and 5, measuring a plurality of groups of data of the transmissivity A-tuning wavelength lambda,the curve is fitted with a gaussian function and the half width and peak transmission of the curve are calculated.