CN201917738U

CN201917738U - Tunable optically-active optical filter

Info

Publication number: CN201917738U
Application number: CN201120005888XU
Authority: CN
Inventors: 张斌; 潘雪丰; 陶卫东; 董建峰
Original assignee: Ningbo University
Current assignee: Ningbo University
Priority date: 2011-01-11
Filing date: 2011-01-11
Publication date: 2011-08-03
Anticipated expiration: 2021-01-11

Abstract

The utility model discloses a tunable optically-active optical filter, which comprises a polarizer and an isotropic optically-active crystal, wherein the polarizer is arranged at any side of the isotropic optically-active crystal, an angle between the surface of the polarizer, which faces towards the isotropic optically-active crystal, and the faced surface of the isotropic optically-active crystal is 33.4 degrees, and the tunable optically-active optical filter has the advantages that: the isotropic optically-active crystal is combined with the polarizer, and at the same time the isotropic optically-active crystal has isotropy, an optically-active chromatic dispersion characteristic and an optical characteristic when a Brewster angle is internally reflected, and the angle between the surface of the polarizer facing towards the isotropic optically-actively crystal and the surface of the isotropic optically-actively crystal which is faced by the polarizer is 33.4 degrees, so the tuning of a continuous spectrum can be effectively realized; since the isotropic optically-active crystal is adopted, compared with an anisotropic optically-active crystal, the requirement on the processing precision is reduced; and since the polarizer and a optically-active material are utilized to realize the filter, not only can the size be reduced, but also the cost is reduced.

Description

A kind of tunable optically-active optical filter

Technical field

The utility model relates to a kind of wave filter, especially relates to a kind of tunable optically-active optical filter.

Background technology

Along with the fast development of optical fiber communication and related industry, tunable optical filter has in fields such as optical fiber technology, light sensing technology, spectral analyses very extensively and important use.

At present, known tunable optical filter mainly contains following several: Mach-Zehnder optical filter, acousto-optic tunable optical filter, distributed feed-back (Distributed Feed Back, DFB) laser adjustable light wave-filter, the humorous wave filter of liquid crystal light-modulating, grating filter, tunable Fabry-Perot wave filter, optically-active optical filter and Lyot type optically-active optical filter etc., it is made that it all is based on interference of light, unusual Bragg diffraction and rotatory dispersion characteristic, and it mainly acts on all is to select some radiation wavelength in continuous or line-spectra.But most of tunable optical filters often can only act on the discrete incident light spectrum with characteristic frequency interval, also or not have tunability; In addition, substantially all be based on quartz crystal as employed tunable optically-active optical filter now, yet quartz crystal needs higher processing precision as a kind of anisotropic gyrotropi crystal when it is used for wave filter, and this utmost point is not easy to the actual application and the reduction of cost.

Summary of the invention

Technical problem to be solved in the utility model provides that a kind of requirement on machining accuracy is low, volume is little, cost is low, and can effectively realize the tunable optically-active optical filter of the tuning filtering of continuous spectrum.

The utility model solves the problems of the technologies described above the technical scheme that is adopted: a kind of tunable optically-active optical filter, it is characterized in that comprising polarizer and isotropy gyrotropi crystal, described polarizer is arranged at the either side of described isotropy gyrotropi crystal, described polarizer towards a surface of described isotropy gyrotropi crystal and its towards the surface of described isotropy gyrotropi crystal between angle be 33.4 °, light source is along the normal orientation incident on a surface of the described dorsad isotropy gyrotropi crystal of described polarizer, the light beam of described polarizer outgoing is with 56.6 ° of described isotropy gyrotropi crystals of incident angle incident, described isotropy gyrotropi crystal inner light beam is with the Brewster corner reflection, and the light beam of described isotropy gyrotropi crystal outgoing is opposite with the parallel beam and the direction of the incident of described isotropy gyrotropi crystal.

Described isotropy gyrotropi crystal is sodium chlorate crystal or sodium bromate crystal.

The white light that described light source adopts white light LEDs or halogen tungsten lamp to send.

Azimuthal change of described polarizer determines spectral line tuning of the light beam of described isotropy gyrotropi crystal outgoing.

Compared with prior art, advantage of the present utility model is by the isotropy gyrotropi crystal is combined with polarizer, simultaneously because the isotropy gyrotropi crystal has isotropy, optical characteristics when rotatory dispersion characteristic and the internal reflection of Brewster angle, and polarizer towards a surface of isotropy gyrotropi crystal and its towards the surface of isotropy gyrotropi crystal between angle be 33.4 °, therefore can make can be with the total reflection of Brewster angle on the reflecting surface 1 of isotropy gyrotropi crystal along the light source of polarizer normal direction incident, and the effect of polarizer can be played in the Brewster angle, thereby can make this wave filter can effectively realize the tuning of continuous spectrum; Because this wave filter adopts the isotropy gyrotropi crystal, compares with anisotropy gyrotropi crystal such as quartz crystal, its requirement to machining precision is lower; Owing to only used the combination of polarizer and optically activ material to realize not only having reduced the volume of wave filter by wave filter, and effectively reduced cost.

Description of drawings

Fig. 1 is the structural principle synoptic diagram of tunable optically-active optical filter of the present utility model;

Fig. 2 is for the white light that adopts halogen tungsten lamp and send during as light source, from the spectrogram of the light beam of isotropy gyrotropi crystal outgoing.

Embodiment

Embodiment describes in further detail the utility model below in conjunction with accompanying drawing.

A kind of tunable optically-active optical filter that the utility model proposes, as shown in Figure 1, it mainly comprises polarizer 3 and isotropy gyrotropi crystal 2, polarizer 3 can be arranged at the either side of isotropy gyrotropi crystal 2 on same surface level, polarizer 3 towards a surface of isotropy gyrotropi crystal 2 and its towards the surface of isotropy gyrotropi crystal 2 between angle be 33.4 °.When using the utility model, light source 1 is along the polarizer 3 normal orientation incident on a surface of isotropy gyrotropi crystal 2 dorsad, and promptly light source 1 vertically is incident in polarizer 3, and the light beam from polarizer 3 outgoing behind polarizer 3 (is Fig. 1 with 56.6 ° of incident angles i ₁The angle) being incident in the isotropy gyrotropi crystal 2, (is among Fig. 1 at isotropy gyrotropi crystal 2 inner light beams with the Brewster angle i _BThe angle) reflection, again along be incident to isotropy gyrotropi crystal 2 in parallel beam and opposite direction from 2 outgoing of isotropy gyrotropi crystal.

In this specific embodiment, adopt isotropy gyrotropi crystal 2 to make tunable optically-active optical filter with isotropy and rotatory dispersion characteristic, it greatly reduces the requirement to machining precision compared to quartz crystal.At this, isotropy gyrotropi crystal 2 is as adopting sodium chlorate crystal or sodium bromate crystal etc.

In this specific embodiment, the white light (natural light) that light source 1 can adopt white light LEDs or halogen tungsten lamp etc. to send.For white light (natural light), when using the utility model, can be directly from the normal orientation incident of polarizer 3.

Tunable optically-active optical filter of the present utility model, the spectral line of the light beam of tuning isotropy gyrotropi crystal 2 outgoing of azimuth angle theta that can be by changing polarizer 3 can change its emergent light spectral range and passband width for the light source that sends continuous spectrum.

Fig. 2 has provided when adopting white light that halogen tungsten lamp sends as light source 1, spectrum from the light beam of isotropy gyrotropi crystal 2 outgoing, as can be seen from Figure 2, in 0～180 ° of scope, regulate the azimuth angle theta of polarizer 3, occur obviously from the spectrum of the light beam of isotropy gyrotropi crystal 2 outgoing, continuous variation, the peak value of spectrum line is to change between 440～670nm at wavelength, promptly when the azimuth angle theta of polarizer 3 changes from 0 ° to 90 °, the peak wavelength of spectrum line is offset towards the 440nm direction, when azimuth angle theta changed from 90 ° to 180 °, the peak wavelength of spectrum line was offset towards the 670nm direction.

Claims

1. tunable optically-active optical filter, it is characterized in that comprising polarizer and isotropy gyrotropi crystal, described polarizer is arranged at the either side of described isotropy gyrotropi crystal, described polarizer towards a surface of described isotropy gyrotropi crystal and its towards the surface of described isotropy gyrotropi crystal between angle be 33.4 °, light source is along the normal orientation incident on a surface of the described dorsad isotropy gyrotropi crystal of described polarizer, the light beam of described polarizer outgoing is with 56.6 ° of described isotropy gyrotropi crystals of incident angle incident, described isotropy gyrotropi crystal inner light beam is with the Brewster corner reflection, and the light beam of described isotropy gyrotropi crystal outgoing is opposite with the parallel beam and the direction of the incident of described isotropy gyrotropi crystal.

2. a kind of tunable optically-active optical filter according to claim 1 is characterized in that described isotropy gyrotropi crystal is sodium chlorate crystal or sodium bromate crystal.

3. a kind of tunable optically-active optical filter according to claim 1 and 2 is characterized in that the white light that described light source adopts white light LEDs or halogen tungsten lamp to send.

4. a kind of tunable optically-active optical filter according to claim 3, the azimuthal change that it is characterized in that described polarizer determine spectral line tuning of the light beam of described isotropy gyrotropi crystal outgoing.