Mirror-monochromator for hard ultra-violet radiation

FIELD: ultra-violet radiation.

SUBSTANCE: the mirror-monochromator has a multi-layer structure positioned on a supporting structure and including a periodic sequence of two separate layers (A,B) of various materials forming a layer-separator and a layer-absorber with a period having thickness d, Bragg reflection of the second or higher order is used. Mentioned thickness d has a deviation from the nominal value not exceeding 3%. The following relation is satisfied: (nAdA + nBdB)cos(Θ) = m λ/2, where dA and dB - the thicknesses of the respective layers; nA and nB - the actual parts of the complex indices of reflection of materials of layers A and B; m - the integral number equal to the order of Bragg reflection, which is higher than or equal to 2, λ - the wave-length of incident radiation and Θ - the angle of incidence of incident radiation. For relative layer thickness Г=dA/d relation Г<0.8/m is satisfied.

EFFECT: provided production of a multi-layer mirror, which in the range hard ultra-violet radiation has a small width of the reflection curve by the level of a half of the maximum at a high reflection factor in a wide range of the angles of incidence.

6 cl, 1 dwg

 

The invention relates to mirrors for hard ultraviolet radiation, which provides monochromatization such radiation.

The optical system for the spectral range of hard ultraviolet radiation (upper edge of the spectrum ultraviolet radiation), which covers wavelengths from approximately 5 to 40 nm, are formed on the basis of multilayer mirrors. Multilayer mirrors consist of alternating layers of two materials, optical constants which differ to the extent possible. For some applications hard ultraviolet radiation, for example in materials science, x-ray astronomy or x-ray microscopy, it is necessary to monochromatization of this radiation. For this purpose it is necessary to reduce the width of the spectral curve of the multilayer reflection mirrors, as measured by half of the maximum peak of the reflection coefficient.

In the literature there are two approaches to reduce this width.

Know the use of cross-structuring by reactive ion etching to create multilayer mirrors from a combination of materials molybdenum/silicon, as described in the work R.Benbalagh, J.M. Andre, R.Barchewitz, M.F.Ravet, A.Raynal, F.Delmotte, F.Nridou, Gjeli, A.Bosseboeuf, R., .Troussel, Nucl. Inst. Meth. Phy. Res. A 458 (3) (2001), 650-655, which allows to reduce the width of the curve coefficients is but the reflection multilayer mirrors in 3 times in comparison with the width of the curve of the reflectivity of multilayer mirrors with the structure of a molybdenum/silicon, optimized for maximum reflectivity.

However, the disadvantage of this treatment is that the lithographic structuring of multilayer structures is very expensive and, in addition, such a multilayer mirrors at an angle of incidence of about 45° there is a significant decrease of the reflection coefficient to R=2%, no comparison with the reflection coefficient R=40%, which is at the same angle of incidence corresponding multilayer mirror, not subjected to lithographic structuring.

It is known that the width of the curve of the reflection multilayer mirrors made of molybdenum/silicon can be reduced by reducing the thickness of the layer of molybdenum, as described in the paper by Y.C. Lim, T. Westerwalbesloh, A.Aschentrup, Acting with their neck occurring, Haindl, U. Kleineberg, U. Heinzmann, Appl. Phys. A72 (2001), 121-124. However, practice shows that reducing the thickness of the molybdenum is only possible to a limited extent, since this thickness is only about 3 nm even in the standard multilayer mirror.

The aim of the present invention is to provide a multilayer mirror, which is in the range of hard ultraviolet radiation has a small width of the reflection curve at half maximum at high reflectance in a wide range of angles of incidence. It is also desirable to overcome the limitations and disadvantages inherent in the prior art.

This goal is in accordance with the present invention is achieved by the features set forth in the independent claim.

Due to the fact that the multilayer structure of the mirror formed by the periodic repetition of the two layers a and b of different materials forming one period thickness d and having the appropriate thickness (dAand din), and

0,97 (dA+dB)≤d≤(dA+dB) 1.03 and

(nAdA+nBdB)·cos(θ)=m·λ/2,

where nAndand nB- real part of complex refractive indices of the materials of the individual layers a and b; m is an integer representing the order of the Bragg reflection, greater than or equal to 2, λ is the wavelength of the incident radiation, and θ - the angle of incidence of the incident radiation in multilayer mirror made according to the present invention can be achieved substantial reduction in the width of the curve reflect the level of half of the maximum when using Bragg reflection of the second or higher order. By reducing the width of the reflection curve at half maximum by using Bragg reflection of a higher order, multi-layered mirror acts as a monochromator, resulting in a significantly simplified structure of the optical system is it for the hard ultraviolet radiation, for example, in synchrotron radiation sources and spectrometers ultraviolet range for plasma sources, where for monochromatization of hard ultraviolet radiation are traditionally used different types of lattices, since the multilayer mirror can be used as a monochromator, and as an element of direction of the beam. No longer necessary to provide additional optical path diffraction grating.

The desired effect is also achieved for the arbitrary case of oblique incidence of waves by taking into account the angle θ fall.

As can be seen from the features of independent claim of the invention, the thickness increase of the period of the structure to an integer number of times necessary to achieve the reflection of the higher order Bragg, which usually leads to a reduction of the reflectivity of multilayer mirrors.

According to the present invention, this reduction of the reflection coefficient arising from the increase in the thickness of the period limited by the fact that when the above-mentioned increase in the thickness period only increases the thickness of the layer (separator layer), whereas the thickness of the layer (absorber layer) remains unchanged compared with the corresponding multilayer mirror, which uses the Bragg reflection of the first order; that is, Rel the relative thickness of the layer A, G=d A/d layer is always less than 0.8/m, where m is an integer corresponding to the order of the Bragg reflection, which is equal to or greater than 2.

In a preferred embodiment of the present invention, according to claim 2, you can achieve even better results if you ensure that the relative thickness D of the layer And was always less than 0.5/m.

One example implementation of the present invention shown in figure 1, and the invention is described in detail with reference to the drawing.

1 schematically shows a cross section of a multilayer mirror-monochromator;

on SIG shows a graph of experimentally measured values of the reflection coefficient.

Figure 1 as an example, schematically shows the multilayer structure of the mirror-monochromator for the hard ultraviolet radiation. Separate the layers a and b, which in each case together form one period, are periodic sequence under a layer D of the coating, which is made, for example, from silicon, it is shown that the dark layer And an absorber layer and has a thickness of dAand shown the light layer is a separator layer and has a thickness of dB. The thickness d of the period is the sum of the thicknesses dAand dBlayers a and B.

The drawing schematically shows four such period, educated SL is s a and b, while the bottom layer is bordered by the substrate S. the thickness of dAand dBlayers in each case the same in all periods, so that the thickness d of a particular period everywhere is the deviation of no more than ±1%; this potential in the industrial production of rejecting guarantees, however, the ability of the present invention to function.

In practice, the layer And the absorber can be performed, for example, of molybdenum and a layer of separator - for example, from silicon. In this structure, the substrate S is a silicon wafer. The number of periods consisting of layers a and b is, for example, 40 so that the penetration depth of the radiation is used to the maximum extent.

In a multi-layer mirror-monochromator, schematically shown in figure 1, uses the second or higher order Bragg reflections. Here, the thickness d of any of the periods in the ideal case, equal to d=dA+dBwhile nAdA+nBdB=m·λ/2, where the complex refractive indices of the materials of the individual layers a and b are determined by the expressionsandso that the optical constants nAndand nInobtained directly from the real parts of the complex refractive index; m is an integer equal to the order of breggovskogo, greater than or equal to 2; and λ is the wavelength of the incident radiation, which should be reflected by the mirror-monochromator with minimal attenuation.

In order in accordance with the above expression to achieve the Bragg reflection of the second or higher order to increase the thickness of a period of an integer times as compared with a conventional multilayer mirror, working on the first order Bragg reflection, and to correspondingly reduce the width of the curve of the reflection coefficient on the level of half of the maximum, but at the same time preserve the value of the reflection coefficient of the mirror at the point of maximum, it only increases the thickness of the layer In the separator, while the thickness of the layer And the absorber does not change compared with the above-mentioned multilayer mirror, working on the first order Bragg reflection. Thus, the relative thickness D=dA/d layer And each period is chosen to satisfy the condition G<0.8 a/m. Even better results can be achieved by choosing G<0,5/m.

Since the material of the separator for multilayer mirrors is chosen so that it made only a very low absorption, reflectance is reduced in this case not as significantly as in the case where the thickness of both layers increases proportionally to achieve the OTP is the manifestation of a higher order reflections in comparison with the multilayer mirror of the first order.

In the simulation, which was carried out for such a multilayer mirror-monochromator with absorber layers of molybdenum and the separator is made of silicon, forming 50 periods for the selected wavelength of 13.5 nm, and the roughness and the presence of layers of mutual diffusion at the boundaries of molybdenum/silicon was not taken into account, were calculated maximum reflectance, theoretically achievable using the above-described structure, and the full width of a peak of the reflection coefficient on the level of half maximum (FWHM) for various orders m Bragg reflection and different thicknesses of the layers In the separator; these results are summarized in table. For example, even for the second Bragg order can be achieved reducing the width of the peak of the reflection coefficient in 2 times. Even to the tenth order Bragg is still possible to achieve a reflection coefficient of more than 25%.

Table 1
mdsi(nm)dMo(nm)d (nm)GRmax(% at 13.5 nm)FWHM (nm)
13,923,006,920,4375,60,631
210,73,0013,70,22 65,70,327
3of 17.53,0020,50,1757,40,220
531,03,0034,00,09644,40,137
1064,83,0067,80,04625,20,080

In the practical implementation of such a multi-layer mirror-monochromator with reflection of the second or third Bragg order and structure, corresponding to the values given in the table for m=2 and m=3 were measured are shown in figure 2 the values of the reflection coefficient depending on the wavelength of deep ultraviolet radiation. It is clear that there is a narrow peak reflectance near the selected wavelength λ, 13.5 nm, and, therefore, achieves the required monochromatization about the desired wavelength λ.

Here is the full width of a peak of the reflection coefficient on the level of half of the maximum is 0,277 nm for the Bragg order m=2 at the maximum reflection coefficient R=53.5 per cent and 0,188 nm for m=3 at the maximum reflection coefficient R=45,3%. In comparison with the known multilayer mirrors, running on the first order Bragg reflection, the width of the peak of the reflection coefficient is about half of the maximum reduced and is less than half or less than one-third.

1. Mirror-monochromator for the hard ultraviolet radiation, comprising a multilayer structure deposited on a substrate in the form of a sequence of individual layers, wherein the multilayer structure is formed by the periodic repetition of the two layers a and b of different materials forming one period of the multilayer structure having a thickness d, the thickness of the respective layers (dAand dBand:

0,97(dA+dB)≤d≤(dA+dB)1.03 and

(nAdA+nBdB)cos(θ)=mλ/2,

where nAand nB- real part of complex refractive indices of the materials of the individual layers a and b; m is an integer equal to the order of the Bragg reflection, which is greater than or equal to 2; λ is the wavelength of the incident radiation and θ - the angle of incidence of the incident radiation; and for the relative layer thickness D=dA/d is the ratio

G<0.8 a/m.

2. Mirror-monochromator according to claim 1, characterized in that the relative layer thickness D=dA/d is the ratio of G<0,5/m.

3. Mirror-monochromator according to claim 1 or 2, characterized in that the materials of the individual layers a and b are molybdenum and silicon.

4. Mirror-monochromator according to claim 1 or 2, characterized in that it has so many periods that the penetration depth p is giving radiation is used to the maximum extent for optimum reflection coefficient.

5. Mirror-monochromator according to claim 1 or 2, characterized in that the surface layer most remote from the substrate, a coating layer.

6. Mirror-monochromator according to claim 1 or 2, characterized in that the width of the spectral curve of the reflection coefficient of the mirror, as measured by the level of half maximum, when using Bragg reflection of the second order (m=2) is reduced approximately two-fold compared with the width of the spectral curve of the reflection coefficient of the mirror when using the Bragg reflection of the first order (m=1), measured by the level of half of the maximum.



 

Same patents:

FIELD: roentgen optics; roentgen ray flux reflecting, focusing, and monochromatization.

SUBSTANCE: proposed method for controlling X-ray flux by means of controlled energy actions on control unit incorporating diffraction medium and substrate includes change of substrate and diffraction medium surface geometry and diffractive parameters of this medium by simultaneous action on control-unit substrate and on outer surface of control-unit diffraction medium with heterogeneous energy. X-ray flux control system has X-ray source and control unit incorporating diffraction medium and substrate; in addition, it is provided with diffraction beam angular shift corrector connected to recording chamber; control unit is provided with temperature controller and positioner; substrate has alternating members controlling its geometric parameters which are functionally coupled with physical parameters of members, their geometric parameters, and amount of energy acting upon them. Diffraction medium can be made in the form of crystalline or multilayer periodic structure covered with energy-absorbing coating.

EFFECT: enhanced efficiency of roentgen-ray flux control due to dynamic correction of focal spot shape and size.

3 cl, 1 dwg

FIELD: X-ray diffraction and X-ray topography methods for studying the structure and quality control of materials during nondestructive testing.

SUBSTANCE: the invention is intended for X-ray beam shaping, in particular, the synchrotron radiation beam, by means of crystals-monochromators. The device for X-ray beam shaping has two crystals-monochromators in the dispersionless diffraction scheme. It is ensured by the possibility of displacement of one from crystals in the direction of the primary beam with crystal fixing in two discrete positions. Both crystals-monochromators have the possibility of rotation for realization of the successive Bragg diffraction. Device for crystal bending has displacement mechanism, two immovable and two movable cylindrical rods, between of which the end parts of a bent crystal are located. The axes of these parts are displaced one in respect to the other. The immovable rods are leaned against the upper surface of a flat parallel plate near its end faces. The L-shaped brackets are attached to the end faces of plate. The parallel surfaces of the brackets contact with immovable rods. The parallel surfaces of the end faces of the upper joints of L-shaped brackets contact with movable rods. The plate with L-shaped brackets is embraced with crooked shoulders of floating rocker with cylindrical pins, installed on the rocker ends. The pins are leaned against the surfaces of movable rods perpendicularly to them. The displacement mechanism is located between the lower surface of plate and middle point of the rocker.

EFFECT: increasing the energy range of X-ray beam when maintaining its spatial position; improving the uniformity of bending force distribution and homogeneity of crystal deformation.

2 cl, 2 dwg

X-ray microscope // 2239822
The invention relates to a projection microscopy with the use of radiation techniques, and more particularly to means for obtaining increased shadow projection of the object, including its internal structure, using x-ray radiation

The invention relates to a means for receiving x-ray radiation, in particular to the means intended for use in the study of substances, materials or devices

The invention relates to measuring equipment

The invention relates to devices for visually-shadow gamma-ray imaging and can be used in industry and in medicine

The invention relates to a method of shifting mosaic scattering of high-oriented pyrolytic graphite (HOPG) in a specified narrow range

The invention relates to a means for fault detection and diagnosis in engineering and medicine that uses radiation in the form of a stream of neutral or charged particles, in particular x-ray radiation, and the means in which this radiation is used for medical purposes or for contact or projection lithography in microelectronics

The invention relates to techniques and technologies for the processing of microstructures and can be used in the manufacture of microelectronic devices

The invention relates to x-ray optics, in particular, to a device for reflection, rotation, divide, focus and monochromatization of x-ray flux and can be used for carrying out processes rentgenovskoi lithography, x-ray microscopy, x-ray spectroscopy, as well as in astronomy, physics, biology, medicine and other fields technique that uses x-rays

FIELD: electric engineering.

SUBSTANCE: integral micromechanical mirror has substrate to place four electrodes onto it. Four additional electrodes of capacitive movement converters are disposed onto the substrate in such a manner to form flat capacitor with mirror element. One additional fixing plate is disposed under mirror element directly onto substrate. There are torsion beams placed in such a way that they connect mirror element with fixing plate. Mirror element, torsion beams, electrodes of electrostatic drives and capacitive converters as well as fixing plate are made of semiconductor material. Area of substrate used for placing integral mirror is reduced. Position of mirror element is subject to control relatively the substrate.

EFFECT: improved reliability of operation.

2 dwg

Mirror // 2265870

FIELD: optical industry.

SUBSTANCE: mirror can be used when producing optical reflecting systems in lasers and experimental physics. Mirror has transparent dielectric base. Metal coating is applied onto the base. Coating has to nanoparticles, for example, silver nanoparticles, which have plasma resonance at electromagnet radiation frequency. The mirror intends to reflect the radiation. Linear dimensions are far smaller than the radiation wavelength. Nanoparticles are applied uniformly onto surface of the base to cover 15% of its area. Thickness of mirror is reduced to minimal size; size of spot of reflected radiation in focus is reduced.

EFFECT: reduced thickness of mirror; improved precision.

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: mirror systems of observation.

SUBSTANCE: coordinates of point of driver's eye and reference point at object to be observed in the driver mirror are measured by rule as well as reference point at mirror of transportation vehicle. Angles of inclination of mirror to coordinate planes are found from relations mentioned in formula of invention. Inclination of driving mirror to coordinate planes is determined. Random point at object of observation is preset and its coordinates are measured by means of measuring tape. Coordinates of point in mirror are calculated where the light beam reflects from the mirror and enters driver's eye. Procedure repeats many times for many random points at object of observation and coordinates of corresponding points of reflection at plane of mirror are found. Shape and sizes of mirror are determined by end points of reflection.

EFFECT: simplified determining of shape and sizes of mirror; improved precision of orientation.

2 cl, 2 dwg

FIELD: optical engineering.

SUBSTANCE: at least two dielectric layers are produced with preset thickness. Layers are disposed one onto the other to form pack of layers. Thickness of layer packs is subject to reduction and thicknesses of separate layers are similarly reduced by means of deforming layer packs to keep relation of thicknesses or relation of thicknesses of layers. Layer pack is disposed between two carrying layers before subjecting the layers to deformation. At least one carrying layer is formed from several separate layers, which are supposed to be disposed subsequently at the end of process of partial deformation at any previous layer of carrying layer. Separate layers of carrying layer can be overlayed onto previous separate layers of carrying layer.

EFFECT: simplified process of manufacture; improved reflection factor.

22 cl

The invention relates to devices used to study cosmic rays, antennas, etc. displayed on the orbit space in the limited volume of the fairing of the launch vehicle, then deployed to larger sizes

The invention relates to television technology, in particular applied to television systems in the far IR range

The invention relates to laser technology and can be used in the manufacture of luminaires solid-state lasers

FIELD: optical engineering.

SUBSTANCE: at least two dielectric layers are produced with preset thickness. Layers are disposed one onto the other to form pack of layers. Thickness of layer packs is subject to reduction and thicknesses of separate layers are similarly reduced by means of deforming layer packs to keep relation of thicknesses or relation of thicknesses of layers. Layer pack is disposed between two carrying layers before subjecting the layers to deformation. At least one carrying layer is formed from several separate layers, which are supposed to be disposed subsequently at the end of process of partial deformation at any previous layer of carrying layer. Separate layers of carrying layer can be overlayed onto previous separate layers of carrying layer.

EFFECT: simplified process of manufacture; improved reflection factor.

22 cl

Up!