JPH02245622A - Polarization interference spectroscope - Google Patents

Abstract

PURPOSE:To measure spectrums at multiple measuring points at a high speed simultaneously at all measuring points over all the wavelengths by arranging a Wollaston prism, two polarizers and a two-dimensional multichannel photodetector. CONSTITUTION:An interference fringe generated at a point of a light source 1 to be measured forms an image in the x-axis at a point A' of a two-dimensional multichannel photodetector 7. Likewise, interference fringes generated at points B and C of the light source 1 form images in the x-axis at points B' and C' of the photodetector 7. In other words, light of the light source 1 is converted into an interference fringe by a polarization interference optical system to be incident into the photodetector 7 with an imaging lens 6. On the other hand, one row of photoelectric elements in the y-axis of the photodetector 7 is made to correspond to each of sections in which the light source 1 is subdivided in the y-axis so that interference fringes in the respective sections are detected with corresponding one row of respective photoelectric elements in the x-axis of the photodetector 7. Thus, spectrums at points of the light source can be obtained corresponding to bits in the y-axis of the photodetector 7 by a reverse Fourier transform of interference fringe waveforms in the x-axis of the photodetector 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polarization interference spectrometer, and particularly to a polarization interference spectrometer suitable for measuring spectra at fixed points on multiple sides.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 59-105508, the conventional device combines interference waveforms spatially obtained by arranging two polarizers with a Wallaston prism in between.
It was configured to be observed using a dimensional multi-channel photoelectric detector.

[Problem to be solved by the invention]

The purpose of the above-mentioned conventional technology is to simultaneously and rapidly measure the entire wavelength range of a spectrum in a measurement area at one point.

An object of the present invention is to provide a polarization interference spectrometer that can measure spectra at multiple measurement points simultaneously and at high speed in all wavelength ranges.

[Means to solve the problem]

The above purpose is to detect the interference waveform spatially and optically formed by a Wallaston prism and two polarizers sandwiching this prism, and to detect the spectrum at multiple measurement points by installing a two-dimensional multichannel photoelectric detector. This is achieved through a configuration that simultaneously measures all measurement points and all wavelength ranges at high speed.

[Effect]

In the present invention, the interference fringes caused by point A of the light source to be measured are
An image is formed in the X-axis direction at point A' of a two-dimensional multichannel photoelectric detector. Similarly, the interference fringes generated by points B and C of the light source to be measured are B' of the two-dimensional multichannel photoelectric detector.
, C' is imaged in the X-axis direction. That is, the light from the light source to be measured is converted into interference fringes (interferogram) by the polarization interference optical system, and is incident on the two-dimensional multichannel photoelectric detector by the imaging lens. Each photoelectric element (bit) in the axial direction
The arrangement of rows corresponds to each section in which the light source to be measured is subdivided in the y-axis direction, and the interference fringes in each section correspond to one row of each photoelectric element in the X-axis direction of the two-dimensional multichannel photodetector. By inverse Fourier transforming each interference fringe waveform in the X-axis direction of the two-dimensional multichannel photoelectric detector, each point of the light source to be measured corresponding to each bit in the y-axis direction of the two-dimensional multichannel photoelectric detector is detected. spectrum can be obtained.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 5.

Fig. 1 is a top view showing an example of the basic configuration of the polarization interference spectrometer of the present invention, Fig. 2 is a side view of Fig. 1, and Fig. 3 is the two-dimensional multichannel photoelectric detector shown in Fig. 1. FIG. 3 is a plan view of the light receiving surface of FIG.

In FIGS. 1 and 2, light 20 emitted from the light source 1 to be measured that spreads in a one-dimensional manner becomes a parallel plane wave 21 by the collimator lens 2, and enters the Wollaston prism 4 via the first polarizer 3.

The Wallaston prism 4 is usually a combination of two wedge-shaped polished birefringent prisms whose crystal axes are orthogonal to each other and bonded together.

The polarization plane of the polarizer 3 is arranged so as to have an inclination angle of 45° with respect to each of the two crystal axes of the Wollaston prism 4, so that the light intensity of the luminous flux split into two by the Wollaston prism 4 is equalized. work to do.

The Wallaston prism 4 divides the incident light beam into two by birefringence, and the two divided light beams are transmitted through the second polarizer 5. The polarization angle of the polarizer 5 is arranged to form an angle of 06 or 90" with respect to the first polarizer 3, and is 45 degrees with respect to each polarization plane of the two divided light beams 22 and 23.
or -45°, so it functions to recombine these light beams, that is, cause them to interfere. As a result, interference fringes are formed locally within the Wallaston prism 4, and the imaging lens 6 forms an image of these interference fringes on the light receiving surface of the two-dimensional multichannel photodetector 7 at an appropriate magnification.

Here, the interference fringes generated from point A of the light source 1 to be measured are 2
An image is formed at point A' of the dimensional multi-channel photoelectric detector 7 in the X-axis direction. Similarly, interference fringes generated by points B and C of the light source 1 to be measured are imaged at points B' and C' of the photoelectric detector 7 in the X-axis direction. That is, the light from the light source 1 to be measured is converted into interference fringes (interferogram) by the polarization interference optical system, and is incident on the two-dimensional multichannel photoelectric detector 7 by the imaging lens 6. The arrangement of -rows of each photoelectric element (bit) in the axial direction corresponds to each section in which the light source 1 to be measured is subdivided in the y-axis direction, and the interference fringes of each section are arranged in the X-axis direction of the photoelectric detector 7. is detected by a row of photoelectric elements.

The coordinates are taken as shown in FIG. 2, and the spectrum at point A of the light source 1 to be measured is defined as Sa(λ). At this time, the waveform of the interference fringe imaged in the X-axis direction at point A' of the two-dimensional multi-channel photoelectric detector 7 (X) is defined as λ1. λ2; Oil wave range of the light source ω; It is a constant determined by the optical system. Since this is a formula for Fourier transforming the spectrum S^(λ) at point A, conversely, the interference fringe waveform processing^(X) is transformed by inverse Fourier transform. By converting, the spectrum S^(λ
) can be obtained. That is, by inverse Fourier transforming each interference fringe waveform I(x) in the X-axis direction of the two-dimensional multi-channel photoelectric detector 7, each of the light sources 1 to be measured corresponding to each bit in the y-axis direction of the photoelectric detector 7 is A spectrum of points S(λ) can be obtained.

FIG. 4 is a block diagram showing an embodiment of the polarization interference spectrometer of the present invention. The diverging light from the light source 9 is turned into a parallel light beam by the collimator 10, and after passing through the object to be measured 11, it enters the polarization interference optical needle 8. Here, the interference fringe waveform at each point on the object to be measured 11 corresponding to the position of the row of photoelectric elements in the y-axis direction of the two-dimensional multichannel photoelectric detector 7 is imaged in the X-axis direction of the photoelectric detector 7 . A signal from each photoelectric element of the photoelectric detector 7 is converted into a digital signal by an A/D converter 12. The arithmetic unit 113 performs inverse Fourier transform on the digital signal of the interference fringe for each row of photoelectric elements in the X-axis direction of the photoelectric detector 7 to calculate a spectrum.

With the device configuration shown in FIG. 4, the transmission and absorbance spectra of multiple points lined up on a straight line of the object to be measured 11 can be measured simultaneously at all points, and
All wavelengths can be measured simultaneously at high speed. In addition, the fourth
Although the figure shows the case of transmitted illumination, the same applies to epi-illumination.

FIG. 5 is a block diagram corresponding to FIG. 4 showing another embodiment of the present invention. The light source 1 to be measured is illuminated by an optical fiber 14 composed of a plurality of pieces, and the light emitted from the end of the optical fiber 14 is collimated by a collimator lens 2 and enters a polarization interference optical system 8.

The light emitted from each fiber of the optical fiber 14 corresponds to each row of photoelectric elements (bits) of the photoelectric detector 7 in the y-axis direction. This makes it possible to rapidly measure the spectra of multiple fixed points that collect light using the optical fiber 14 at all points simultaneously and at all wavelengths simultaneously.

(Effects of the Invention) According to the present invention described above, there is an effect that spectra at multiple measurement points can be measured at all measurement points and all wavelengths simultaneously and at high speed.

[Brief explanation of drawings]

Fig. 1 is a top view showing an example of the basic configuration of the polarization interference spectrometer of the present invention, Fig. 2 is a side view of Fig. 1, and Fig. 3 is the two-dimensional multichannel photoelectric detector shown in Fig. 1. FIG. 4 is a block diagram showing one embodiment of the polarization interference spectrometer of the present invention, and FIG. 5 is a block diagram corresponding to FIG. 4 showing another embodiment of the present invention. 1... Light source to be measured, 2... Collimator lens, 3...
...first polarizer, 4...Wollaston prism,
5... Second polarizer, 6... Imaging lens, 7...
Two-dimensional multichannel photoelectric detector, 8... Polarization interference optical system, 9... Light source, 1o... Collimator, 11.
...Measurement object, 12... A/D converter, 13... Arithmetic device, 14... Optical fiber.

Claims (1)

[Claims] 1. A light source to be measured, a Wollaston prism, and two polarizers having a plane of polarization in a direction of 45° with respect to the crystal axis of the Wollaston prism and placed at positions sandwiching the Wollaston prism. , in a polarization interferometer consisting of a photoelectric detector that detects an optically formed interference waveform, a two-dimensional multi-channel photoelectric detector is provided as the photoelectric detector, and spectra at multiple measurement points are measured at all measurement points, A polarization interference spectrometer characterized by a configuration that allows high-speed measurement in all wavelength ranges simultaneously.