Conical diffraction grazing incidence spectrometer and diffraction grating for use in the spectrometer

    公开(公告)号:US20030016355A1

    公开(公告)日:2003-01-23

    申请号:US10191993

    申请日:2002-07-10

    CPC classification number: G02B5/1861 G01J3/18 G01J3/1833 G01J3/189

    Abstract: An x-y coordinate is set on the surface of diffraction grating 3 with non-uniformly spaced grooves and expressed by the following series expansion which is a groove function describing a point (w,l) on the nth groove from the origin: 1 n = 1 null null null i , j null n i null null null j null w i null l j null null null ( i + j null 1 ) The focal length (r0null) and the expansion coefficient nij in this series expansion are so determined that all expanded terms Fij in the following optical path function are zero at a desired wavelength: 2 F = null i , j null F i null null null j null w i null l j = null i , j null [ M i null null null j + ( m null null null null null ) null n i null null null j ] null w i null l j null null null ( i + j > 0 ) the optical path being for the light that passes through entrance slit 1 to be reflected by concave mirror 2 and diffracted at a point (w,l) on the surface of diffraction grating 3 before it reaches exit slit 4. The positions of two point light sources C5 and D6 in a holographic recording system are so determined as to realize the required value of nij.

    Simultaneous Multi-Angle Spectroscopy

    公开(公告)号:US20170356800A1

    公开(公告)日:2017-12-14

    申请号:US15344825

    申请日:2016-11-07

    Abstract: Methods and systems for performing simultaneous spectroscopic measurements of semiconductor structures over a broad range of angles of incidence (AOI), azimuth angles, or both, are presented herein. Spectra including two or more sub-ranges of angles of incidence, azimuth angles, or both, are simultaneously measured over different sensor areas at high throughput. Collected light is linearly dispersed across different photosensitive areas of one or more detectors according to wavelength for each subrange of AOIs, azimuth angles, or both. Each different photosensitive area is arranged on the one or more detectors to perform a separate spectroscopic measurement for each different range of AOIs, azimuth angles, or both. In this manner, a broad range of AOIs, azimuth angles, or both, are detected with high signal to noise ratio, simultaneously. This approach enables high throughput measurements of high aspect ratio structures with high throughput, precision, and accuracy.

    Echelle spectrometer with a shaped oriented slit
    6.
    发明授权
    Echelle spectrometer with a shaped oriented slit 失效
    Echelle光谱仪具有成形定向的狭缝

    公开(公告)号:US5719672A

    公开(公告)日:1998-02-17

    申请号:US721148

    申请日:1996-09-26

    Inventor: Ring-Ling Chien

    CPC classification number: G01J3/1809 G01J3/189

    Abstract: An improved echelle spectrometer comprises a slit in light blocking plate, an echelle grating, and a detector array. The slit is shaped and oriented to align an image of a light beam projected through the slit, onto the echelle grating and onto the detector in a desired orientation and shape relative to the detector array. Precise adjustment of the shape and orientation of the slit is dependent on the orientation of the detector with respect to the dispersion direction of the echelle grating. The echelle spectrometer provides high detector resolution with reduced read-out time.

    Abstract translation: 改进的电子光谱仪包括遮光板中的狭缝,梯形光栅和检测器阵列。 狭缝被成形并定向成使得通过狭缝投射的光束的图像以相对于检测器阵列的期望的取向和形状对准到梯形光栅并且到达检测器上。 狭缝的形状和取向的精确调整取决于检测器相对于梯形光栅的色散方向的取向。 梯形光谱仪提供高检测器分辨率,减少读出时间。

    Monochromator with concave grating
    7.
    发明授权
    Monochromator with concave grating 失效
    具有凹面光栅的单色器

    公开(公告)号:US4455088A

    公开(公告)日:1984-06-19

    申请号:US347417

    申请日:1982-02-10

    Applicant: Masato Koike

    Inventor: Masato Koike

    CPC classification number: G01J3/1838 G01J3/189

    Abstract: A constant deviation monochromator with a holographically formed concave grating and entrance and exit slits positioned on opposite sides of the plane including the Rowland circle of the grating, wherein the grating has been formed by using two coherent light sources positioned on the same side of the Rowland plane, whereby aberrations and stray light are substantially reduced.

    Abstract translation: 具有全息形成的凹形光栅的恒定偏差单色仪和位于包括光栅的罗兰圆的平面的相对侧上的入射和出射狭缝,其中通过使用位于罗兰的同一侧上的两个相干光源形成光栅 从而大大减少像差和杂散光。

    Monochromator having a concave holographic grating
    8.
    发明授权
    Monochromator having a concave holographic grating 失效
    具有凹凸全息图的单色显影剂

    公开(公告)号:US4068954A

    公开(公告)日:1978-01-17

    申请号:US647767

    申请日:1976-01-09

    Inventor: Edouard Da Silva

    CPC classification number: G01J3/02 G01J3/0243 G01J3/1838 G01J3/189

    Abstract: A monochromator having a concave holographic grating which is turnable in rotation and provided with an inlet slot parallel to the lines of the grating for incident light and an outlet slot also parallel to the lines of the grating, the inlet and outlet slots being disposed on opposite sides of a diametrial median plane P of the grating extending perpendicular to the lines of the grating and passing through the center of the grating. The bisector of the angle A, formed by two lines connecting the center of each slot to the center of the grating is contained in the plane P, the slots being additionally disposed such that the projection .alpha. of the angle A on the plane P is .ltoreq. 3.degree. and the projection .beta. of the angle A on the plane P' containing the bisector and perpendicular to the plane P is .ltoreq. 15.degree.. Two elementary monochromators can be connected in series and the gratings of the elementary monochromators are carried by a common rotation shaft, the image of the outlet slot of one elementary monochromator being sent to the inlet slot of the following monochromator by an optical system composed of planar mirrors, and a spherical mirror extending parallel to the gratings and turnable around an axis parallel to the axis of the shaft. SUFIELD OF THE INVENTIONThe invention relates to a monochromator having slots and a concave holographic grating, and more particularly, by way of example, to a monochromator adapted to the study of RAMAN spectrums. The invention is also related to apparatus realized by the coupling of a plurality of monochromators of this type.BACKGROUNDThere are known optical monochromators having a grating which for example have described on pages 78 to 81 in, "Applied Optics and Optical Engineering," by Robert J. Meltzer, edited in 1969 by Rudolf Kingslake. The grating monochromators at first utilized a planar grating which necessitated the use of a collimator and an objective. These optical auxiliary members introduce aberrations which generate errors and these have been remedied by the use of concave grating which eliminate the objective and the collimator. The concave gratings, usually engraved, are astigmatic and this deficiency has been recently overcome by the use of concave holographic gratings which reduce the aberrations, notably when they are utilized at optimum angles. These diffraction gratings are manufactured, in particular, by the SOCIETY INSTRUMENTS. S.A., at Longjumeau, France. This society has edited a technical brochure which discloses holographic gratings and the physics of diffraction gratings.These documents which well illustrate the current state of the art, show that in such known monochromators the inlet and outlet slots are disposed parallel to the lines of the grating and the center of each slot is in a diametral, median plane P of the surface of the grating. The diametal plane itself is perpendicular to the lines of the grating. FIG. 1 shows in very simplified manner this state of the art. Therein in frontal view there is seen a concave grating 31 whose diametral median plane P perpendicular to the lines of the grating, is represented by phantom line 32. The light to be analyzed is passed through the inlet slot 33, and the monochromatic light which is sought is isolated by the outlet slot 34. It is seen that the slots 33 and 34 are each symetrically disposed with respect to the plane P, and the lateral spacing between these slots is relatively substantial. The inlet and outlet slots are fixed and the grating is turnably mounted to selectively make the outlet slot face the portion of the spectrum that one wishes to utilize. It can, therefore, frequently occur unexpectedly that a portion of the spectrum spreads itself to the zone of the inlet slot, thus introducing parasitic light into the system. This disadvantage is not very serious for monochromators operating with sources of relatively great luminosity, but in contrast it becomes a very substantial disadvantage when one operates with RAMAN spectrums. The very low intensities of these rays requires the elimination of all parasitic light and it is also for this reason that monochromators having concave, holographic gratings are utilized which operate under good conditions without the ue of auxiliary optical elements for collimation and for focusing.It is also known in the case of conventional monochromators of the type of FIG. 1 that with a relatively substantial angle of deviation between the mean incident ray passing through the center of the slot and the peak of the grating, and the mean diffracted ray issuing from the peak of the grating and passing through the center of the outlet slot that the quality of the formed spectral image is a maximum in the vicinity of the diametral plane. Similarly, the quality of the spectral image is best if the entry slot only extends slightly on opposite sides of the median plane. For a good quality of image, one seeks, therefore, generally, to utilize inlet and outlet slots of short lengths. This is not a disadavantage when the luminosity is great, but for the study of RAMAN spectrums, having low energy, one is obliged to utilize relatively long slots and the images of the extremities present aberrations resulting in a loss of resolution of the apparatus.SUMMARY OF THE INVENTIONAn object of the present invention is to provide a monochromator which simultaneously permits the use of long slots with good image qualities and avoids the introduction of parasitic light due to the spreading out of the spectrum to the inlet slot.According to the invention, in a monochromator having a concave, holographic grating orientable in rotation and provided with an inlet slot parallel to the lines of the grating for the incident light, and an outlet slot also parallel to the lines of the grating, the inlet and outlet slots are each disposed entirely on opposite sides of the median. diametral plane P of the grating extending perpendicualr to the lines of the grating and passing through the peak or center of the grating, the bisector of the angle A, formed by lines connecting the center of each slot to the peak of the grating being contained in the plane P, the slots being additionally disposed such that the projection .alpha. of the angle A, on the plane P is .ltoreq. 3.degree. and the projection .beta. of the angle A on the plane P' passing through the bisector and perpendicular to the plane P is .ltoreq.15.degree..

    Abstract translation: G。

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