Interference light filter with adjustable band pass

FIELD: physics.

SUBSTANCE: interference light filter has a Fabry-Perot resonator in form of two plates with mirror coatings placed with a gap between them on holders of a mechanism for moving the plates. Between the mirror coating and the plate there is a compensation layer whose thickness varies in accordance with a law which provides equivalent arrangement of the mirror coatings relative each other.

EFFECT: simple design due to exclusion of an adjustment device and easier manufacturing due to simplification of requirements for the plane of the plates and exclusion of the adjustment process.

1 dwg

 

The invention relates to optics, optical devices, based on the use of interference of light beams, for example, Fabry-Perot cavities, used in scientific research and technology for spectral analysis and monochromatization of light.

Analogue of the invention are widely known interference filter [1], which consists of two parallel partially transparent mirrors to the agreement concluded between them a thin dielectric layer. The radiation passing through the filter undergoes multiple reflections between the mirror surfaces, with each reflection is partially coming out. Output the system produces an infinite sequence of decreasing amplitude rays with equal difference between them, which interfere between them; the transmission spectrum of such filters contains several narrow lines.

The disadvantage of this filter is the inability of the frequency tuning bandwidth.

As the prototype is set to a known type of dispersive elements of the spectral optical devices - scanning Fabry-Perot interferometer [1]. The main part of the prototype are two partially reflecting mirrors parallel to each other. Mirrors can be deposited on adjacent surfaces of two parallel glass plates, the distance between the cat is whom you can modify a special mechanism.

The disadvantages of the prototype: the complexity of the design, due to higher requirements for allowable flatness of the gap between the plates is of the order of hundredths - tenths of the wavelength of the radiation; this condition requires the inclusion in the device adjusting mechanism, as well as the significant cost to the manufacture of plates and complexity of setting up the device after manufacture due to the necessity of conducting the process of alignment with the control of the relative position of the plates.

The solution is achieved by the interference filter with tunable bandwidth, contains a Fabry-Perot interferometer in the form of two plates with a mirror coating, mounted flat gap between a holder mechanism for moving the plates according to the invention is proposed between the mirror surface and plate positioning compensation layer, the thickness of which varies according to the law, providing the equidistant arrangement of the mirror coatings relative to each other.

New in the proposed device is controlled filter is that between the mirror surface and the plate is of the compensation layer, the thickness of which varies according to the law, providing the equidistant arrangement of the mirror layers mentioned the reason the Torah.

The proposal be placed in the cavity between the mirror surface and the plate of the compensation layer, the thickness of which varies according to the law, providing the equidistant arrangement of the mirror layers of the resonator, i.e. compensating its thickness possible local irregularities of the surfaces of the plates allows you to get almost completely flat, the gap between the mirror surfaces of the resonator even in the case of plates with the roughness of their surfaces. If the layer is put into place after the plates are fixed in the mechanism of their movement, providing a function to change the gap between the mirror surfaces and the rebuilding of the resonator, it eliminates the need for adjustment of the location of plates.

Thus, simplifies the design of the controlled filter, eliminating the need for adjusting the device, facilitates the production of color filter by simplifying requirements for the flatness of the plates, which are substrates of mirror layers, and by eliminating the process of alignment.

The drawing shows schematically the proposed device in cross section. Here 1 and 2 are transparent plates 3 and 4 mirror cover plates, 5 - compensating layer 6 - the air gap between the mirror coatings; mirror pokrytii the gap to form a cavity Fabry-Perot. Plates 1 and 2 mounted on holders 7 and 8 of the mechanism for moving the plates.

The arrow shows the direction of movement of the top in the drawing plate 2. Plate 2 is attached to the holder glued connection 9.

The device provides equidistantly gap 6 between the mirror surfaces 3 and 4 due to the fact that the compensating strip 5 has a thickness greater where the surface of the plate 2 holes, and smaller where the protrusions; as a result, the size of the gap is the same everywhere. When moving plate, which is necessary for the restructuring of the resonator, the transfer mechanism should support strictly translational movement of the plate.

The manufacturer of the device may be as follows.

On the plate 1 with a mirror coating is applied to the sacrificial layer with the same thickness as the desired gap resonator, for example, by spraying in a vacuum; the thickness of the layer is obtained exactly the same throughout its useful square. On top of the sacrificial layer is applied to the mirror cover 4, then the non-shrink layer of adhesive; placing plate 2 and the resulting Assembly is placed on the holder transfer mechanism, greased the same glue. After hardening of the adhesive, the sacrificial layer is removed, for example, by dissolving in a suitable solvent.

In the manufacture of devices used conventional optical p is izvodstv materials: glass plates, aluminum for plating, optical adhesives.

Thus, confirms the possibility of solving the task: to simplify the design of the device tunable optical filter and to facilitate its manufacture.

The invention can be applied in optotechnik, for example , optical radiation monochromators, spectrometers, and other advantages of the device before known is its compact size - it can be made in the size of the chip of the chip.

Sources of information

1. Skokov IV Multibeam interferometers in measurement technology. - M.: Mashinostroenie, 1989.

An interference filter with tunable bandwidth containing the resonator Fabry-Perot in the form of two plates with a mirror coating, mounted with a gap between a holder mechanism for moving the plates, characterized in that between the mirror surface and the plate is of the compensation layer, the thickness of which varies according to the law, providing the equidistant arrangement of the mirror coatings relative to each other.



 

Same patents:

FIELD: physics.

SUBSTANCE: fibre-optic connector has first and second half couplings for sealing first and second sections of optical fibre on whose butt ends there are first and second pairs of step-up and step-down optical multi-layer transformers. There is an air gap between the outer layers of the first and second pairs of optical multi-layer transformers. Layers of the first and second pairs of optical multi-layer transformers are made from materials with different refraction indices and are measured from outer layers of step-down transformers of the first and second pairs of optical multi-layer transformers adjacent to the air gap towards the butt ends joined to optical fibre sections. Thickness of each layer is equal to a quarter of the medium wave Xo of the signal transmitted over the optical fibre and the number of layers is selected based on conditions given in the formula of invention.

EFFECT: lower level of power loss arising due to insufficiently close contact or welded joint at the position of the joint and wider range of apparatus for this purpose.

4 cl, 7 dwg

FIELD: physics.

SUBSTANCE: fibro-optical connector comprises first and second half-couplings to receive first and second sections of optical fiber. First and second pairs of step-down optical multilayer transformers are arranged on end faces of said sections. Air gap is arranged between outer layers of said first and second pairs of said transformers. Layers of first and second pairs of aforesaid transformers are made from materials with differing indices of reflection and are counted from outer layers of aforesaid transformers in direction of the end faces of connected sections of optical fiber. Thickness of every layer makes one fourth of average signal wave λ0 transmitted over optical fiber, while the number of layers is selected subject to conditions covered by invention claim.

EFFECT: reduced power loss, expanded performances.

4 cl, 9 dwg

FIELD: physics, optics.

SUBSTANCE: tunable optical filter with Fabry-Perot interferometre has transparent plates with mirror coatings with spacing in between. When making the said optical filter, a sacrificial layer is deposited on one plate with the mirror coating. A mirror coating is then deposited on top and the second transparent plate is attached through a layer of hardening material. After that the said plates are attached to holders through a hardening material and the sacrificial layer is removed through evaporation by heating to temperature below the thermal destruction temperature of the hardening layer.

EFFECT: easier obtaining of controlled spacing between plates, avoiding use of special methods of obtaining surfaces with high degree of flatness, avoiding the need to monitor the value of the spacing and its wedge.

1 dwg

FIELD: physics.

SUBSTANCE: invention concerns area of optical thin-film coatings. The spectral divider contains the optical interference system with alternating quarter wave layers; part of them has an optical thickness not multiple to quarter of length of an emission wave. The spectral divider design allows obtaining the optimised spectral characteristics having small fluctuations of the transmittance factor in a working range of transparency.

EFFECT: spectral divider can be used at a direct and inclined light ray tilt angle in various geodetic devices and special purpose devices.

2 cl, 4 dwg

FIELD: fibre-optic communication, optical multilayer filters.

SUBSTANCE: optical multilayer filter (OMLF) consists of an input optical transformer (In. OT 1), a selective part (SP 2), and output optical transformer (Out. OT 3) and substrates 5, 6. The In. OT 1, SP 2, and Out. OT 3 consist of NIn=2s, Nsp=4k and Nout=2r alternating layers 7 and 8, respectively, with high nh and low nl values of refractive indices of materials they are made of. The thickness of every layer d=0.25λ, where λ is the mean OMFL bandwidth wave length. Refractive indices of adjoining layers of the In OT and SP, and those of SP and Out.OT are equal. Note that the SP alternating layers are made from materials with refractive indices mirror-symmetric relative to the SP centre. The first layer of In. OT and the last layer of Out. OT are connected to substrates. Proposed are the relations to calculate the parameters of claimed arbitrary type OMLF.

EFFECT: reduction of signal distortion to preset magnitude in a wide frequency range of the filter attenuation in the preset bandwidth and increase in attenuation to the preset magnitude that allows wider application of the aforesaid filters.

3 cl, 7 dwg

FIELD: fiber-optic transmission systems.

SUBSTANCE: optical multilayer filter has N dielectric layers made of materials with different refractivity. Optical thickness of any layer equals to λ/4, where λ average wavelength of transmission band of optical filter. Optical multilayer filter is composed of input optical transformer, selective part and output optical transformer. Level of signal distortions is reduced till preset value for wide range of frequency characteristics of decay of filter within preset transmission band and decay is improved within delay band till preset value.

EFFECT: widened area of application.

5 dwg

FIELD: narrowband filtration covers.

SUBSTANCE: narrowband filtration cover contains two systems of alternating dielectric layers with different refraction coefficients and equal optical thickness λ0/4, in the form of high reflection mirrors, and a dielectric layer dividing them. In accordance to the invention, structure of high reflection mirrors additionally features dielectric layers with intermediate value of refraction coefficient and dividing layer has optical thickness λ0 or one divisible by it, and sequence of layer alternation has form (CBCABA)KD(ABACBC)K with nA<nB<nC, where refraction coefficient of dividing layer nD is not equal to nA (for example, nD=nC) and k≥1 is an integer number, where: λ0 - maximal filtration cover throughput wave length; A, B and C - dielectric layers with values of refraction coefficient nA, nB and nC respectively, and D - dividing layer.

EFFECT: increased selectivity due to expansion of high reflection bands on the sides of pass band.

5 dwg

FIELD: optical instrument engineering.

SUBSTANCE: optical filtering device can be used for building devices for spectral filtration of optical images, for example, for wavelength re-tune optical filters, IR imagers working within specified narrow spectral ranges. Filtering device being capable of re-tuning within preset wavelength range is based upon interferometers. Interferometers are disposed along path of filtered radiation flow at different angles to axis of flow. Reflecting surfaces of plates of any interferometer, which plates are turned to meet one another, are optically polished and they don't have metal or interference mirror coatings. To filter selected wavelength of λm; the following distances among reflecting faces of interferometers: d1=(λm/2)k, k=1 or k=2, dn=(n-1)d1 or nd1. Filtering device is equipped with different filters which cutoff radiation outside borders of range to be filtered, including filters which are made of optical materials being transparent within band of spectral characteristic of sensitivity of consumer's receiver, which receiver registers filtered radiation. Filter cutting off short wavelength radiation is made of materials, which form border with positive derivative of dependence total internal reflection angle depending on wavelength. Filter cutting off long wavelength radiation is made of materials which form border with negative derivative of angle of total internal reflection depending on wavelength.

EFFECT: improved stability of parameters; increased transmission ability in maximal points of bands and reduction in number of transmission bands; increased relative aperture; higher quality of filtration; reduced number of side maximums.

4 cl, 5 dwg

FIELD: optical engineering.

SUBSTANCE: device can be used for getting image from space, including surface of Earth, from space and from different sorts of air carriers. Device has at least one information channel which channel has objective, filter and multi-element receiver. Filter is made of two lenses, which lenses form flat-parallel plate. Lenses are made of the same material with equal radiuses of curvature of their spherical surfaces. Interference coatings are applied onto spherical surfaces, which coatings form, together with material of lenses, spectral range of device. Filter can be installed between objective and radiation receiver. In this case the first lens is made flat convex, the second one is flat concave. Center of radius of curvature of spherical surface of flat-convex lens is brought into coincidence with center of exit pupil of objective. Filter can be installed in front of objective.

EFFECT: constancy of borders of spectral sensitivity and of level of transmission within total area of angle of view; improved precision of measurement.

7 cl, 3 dwg

Reflecting surface // 2256942

FIELD: optical instrument engineering.

SUBSTANCE: invention can be used for wide-band light reflecting. Reflecting surface has dielectric layers A, B and C. A layer is made of material having low refractivity, B layer is made of material with average refractivity and C layer is made of material having high reflectivity. Optical thickness of layers equals to λr/4, where λr is wavelength of middle part of interval having high refractivity. Sequence of layer alternation looks like (CDCABA)KCBC, where K>=and has to be integer. Spectrum range with high reflectivity is widened due to shift in adjacent bandwidths at opposite sides along wavelength scale.

EFFECT: widened spectrum range with higher refractivity.

5 dwg

FIELD: physics.

SUBSTANCE: method of determining refraction index of surface electromagnetic waves (SEW) involves formation of an interference pattern resulting from interference of the reference electromagnetic wave with a wave produced by the initial beam of surface electromagnetic waves. The reference wave is in form of a new beam of surface electromagnetic waves, formed by separating part of the rays from the initial beam, where plane wave fronts are chosen. An interference pattern is formed through superposition of both beams of surface electromagnetic waves, and the said pattern is recorded in a plane which is parallel the surface of the sample.

EFFECT: increased accuracy and cutting on measurement time.

3 dwg

FIELD: physics; optics.

SUBSTANCE: present invention pertains to optics. Proposal is given of a substrate on which there is a Fabri-Pero filter, consisting of at least three layers. The first and second light reflecting layers of the filter, whose outer reflecting surfaces face each other, are separated by a gap with thickness, d, in which there is a transparent intermediate layer. The reflecting layers are made from the same basic material, and the intermediate layer is made from a substance which is a chemical compound of this basic material with another material.

EFFECT: filter can be deposited in one working stroke in a single vacuum coating device using a single evaporating device.

11 cl, 3 dwg

FIELD: optical instrument engineering.

SUBSTANCE: optical filtering device can be used for building devices for spectral filtration of optical images, for example, for wavelength re-tune optical filters, IR imagers working within specified narrow spectral ranges. Filtering device being capable of re-tuning within preset wavelength range is based upon interferometers. Interferometers are disposed along path of filtered radiation flow at different angles to axis of flow. Reflecting surfaces of plates of any interferometer, which plates are turned to meet one another, are optically polished and they don't have metal or interference mirror coatings. To filter selected wavelength of λm; the following distances among reflecting faces of interferometers: d1=(λm/2)k, k=1 or k=2, dn=(n-1)d1 or nd1. Filtering device is equipped with different filters which cutoff radiation outside borders of range to be filtered, including filters which are made of optical materials being transparent within band of spectral characteristic of sensitivity of consumer's receiver, which receiver registers filtered radiation. Filter cutting off short wavelength radiation is made of materials, which form border with positive derivative of dependence total internal reflection angle depending on wavelength. Filter cutting off long wavelength radiation is made of materials which form border with negative derivative of angle of total internal reflection depending on wavelength.

EFFECT: improved stability of parameters; increased transmission ability in maximal points of bands and reduction in number of transmission bands; increased relative aperture; higher quality of filtration; reduced number of side maximums.

4 cl, 5 dwg

The invention relates to the field of astrophysical measurements and can be used to monitor one of the most important parameters of the solar image, namely functions to limb darkening

The invention relates to the field of optical instrumentation and can be used to study the microinhomogeneities in transparent media

The invention relates to an optical instrument, in particular an interference devices designed to scan the spectrum for the spectral analysis of optical radiation with high precision and high resolution, it can be used as scanning and tunable Fabry-Perot interferometer, as well as for selection of the longitudinal modes of the laser radiation

The invention relates to techniques for the measurement of optical methods of correlation and coherence functions of the turbulent environments located between the light source and the interferometer

The invention relates to the technical physics, in particular to the optical instrument, intended for long-term observations of astronomical sources at a given wavelength and can be used in meteorology, nuclear studies and spectral studies of laboratory sources

The invention relates to optics and can be used in interferometry, spectroscopy, laser technology, optical production

FIELD: optical instrument engineering.

SUBSTANCE: optical filtering device can be used for building devices for spectral filtration of optical images, for example, for wavelength re-tune optical filters, IR imagers working within specified narrow spectral ranges. Filtering device being capable of re-tuning within preset wavelength range is based upon interferometers. Interferometers are disposed along path of filtered radiation flow at different angles to axis of flow. Reflecting surfaces of plates of any interferometer, which plates are turned to meet one another, are optically polished and they don't have metal or interference mirror coatings. To filter selected wavelength of λm; the following distances among reflecting faces of interferometers: d1=(λm/2)k, k=1 or k=2, dn=(n-1)d1 or nd1. Filtering device is equipped with different filters which cutoff radiation outside borders of range to be filtered, including filters which are made of optical materials being transparent within band of spectral characteristic of sensitivity of consumer's receiver, which receiver registers filtered radiation. Filter cutting off short wavelength radiation is made of materials, which form border with positive derivative of dependence total internal reflection angle depending on wavelength. Filter cutting off long wavelength radiation is made of materials which form border with negative derivative of angle of total internal reflection depending on wavelength.

EFFECT: improved stability of parameters; increased transmission ability in maximal points of bands and reduction in number of transmission bands; increased relative aperture; higher quality of filtration; reduced number of side maximums.

4 cl, 5 dwg

Up!