Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
  • G01J3/12—Generating the spectrum; Monochromators
  • G01J3/18—Generating the spectrum; Monochromators using diffraction elements, e.g. grating
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
  • G02B19/0019—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
  • G02B19/0023—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors) at least one surface having optical power
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
  • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
  • G02B19/0052—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a laser diode
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
  • G02B19/009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with infrared radiation
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
  • G01J3/02—Details
  • G01J3/06—Scanning arrangements arrangements for order-selection
  • G01J2003/061—Mechanisms, e.g. sine bar
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers

Definitions

• the invention relates to a monochromator arrangement with an adjustable grating monochromator whose beam
• the invention is based on the object of creating a monochromator arrangement which can subsequently be inserted into an external beam path of an spectrometer having an intermediate focus after it has already been adjusted, this adjustment 5 being full should be preserved.
• This object is achieved according to the invention in that the grating onochromator is assigned a planar deflection device, by means of which the entrance focus and the exit focus are imaged in one and the same intermediate focus of an outer beam path which is transverse to the connecting line between the entrance focus and the exit extends the lattice monochromator.
• the entry and exit beams are deflected by deflecting mirrors such that the entry and exit focus come to a point, the entry and exit directions being identical.
• the monochromator arrangement can be operated in an intermediate focus of an optical laser spectrometer structure without influencing the outer beam path.
• a diffraction grating is used in the monochromator arrangement to increase the dispersion twice and at a large angle. In this way, a sufficiently high resolution for mode selection is achieved even with a small grating of only about 30 mm edge length. Due to the possibility of getting by with a small grating, the monochromator arrangement can be made very narrow, which enables a series arrangement at a short distance.
• An off-axis parabolic mirror is used as a collimator in the monochromator in order to achieve diffraction-limited and astigmatism-free imaging.
• the deflection device of the monochromator arrangement it is possible to bring the input focus of the monochromator to the location of an intermediate focus of the outer beam path and also to mirror the output focus of the monochromator by mirroring in the same intermediate focus in such a way that the monochromator restores the outer beam path and from the outside like one Pinhole with spectral filter effect appears.
• the deflection device is an integral part of the monochromator arrangement.
• the monochromator arrangement can be reproducibly inserted into a free intermediate focus of the outer spectrometer arrangement by means of a centering pin.
• FIG. 1 shows a monochromator arrangement according to the invention in a side view, partly in section
• FIG. 3 shows the deflection device according to FIG. 2 in a view from above
• 4 shows the basic beam path of the monochromator in a schematic side view and 5 shows the basic beam path of the monochromator assigned to the deflection device in a plan view.
• the monochromator arrangement shown in FIG. 1 has a monochromator housing 1 and a deflecting device housing 2, which is designed as a plug-in part and is provided with a centering pin 3 at its lower end in FIG. 1.
• the converging outer beam path 4 comes from the light of a tunable infrared laser, which is not shown in the drawing and with highly resolving spectroscopy , e.g. used in quantitative gas analysis.
• the light of the laser not shown in the drawing, is focused on an intermediate focus 6, which is assigned to the converging outer beam path 4 and the diverging outer beam path 5.
• the diverging outer beam path 5 arrives at a measuring section, also not shown in the drawing, and finally to a detector, not shown in the drawing.
• the intermediate focus 6 lies within the deflecting device housing 2, as can best be seen in FIGS. 2 and 3, in the opening of the entrance aperture 7 of the monochromator arrangement.
• the opening of the perforated aperture 7 simultaneously forms the entry focus 8 for the monochromator 9 arranged in the monochromator housing 1.
• the longitudinal axis of the centering pin 3 passes through the intermediate focus 6 and the entry focus 8. If the monochromator arrangement shown in FIG. 1 is removed from the beam path of the laser spectrometer (not shown), the position of the converging outer beam path 4 and diverging outer beam path 5 shown in FIG. 1 does not change.
• the monochromator arrangement shown in FIG. 1 therefore acts like a pinhole with a spectral filter effect.
• Deflecting mirror 10 which has the shape of an X letter in a side view in FIG. 1 together with a second deflecting mirror 11 and can be seen more clearly in FIGS. 2 and 3.
• the first deflecting mirror 10 deflects the laser light upwards by 90 °, the deflected beam being provided with the reference symbol 12 in FIGS. 1 and 2.
• the deflected beam 12 forms the input beam for the monochromator 9 arranged in the monochromator housing 1.
• the output beam 13 of the monochromator 9 is shown in FIGS. 1, 2 and 4 overlapping with the input beam 12, although, as can best be seen in FIGS. 3 and 5, the output beam 13 when leaving the monochromator 9 compared to the Input beam 12 is offset transversely to the direction of propagation of the outer beam path 4, 5, so that the output beam 13 strikes the second deflection mirror 11, which, as shown in FIG. 3, transversely to the direction of propagation 14 of the outer beam path 4, 5 by an amount V is laterally offset.
• an exit perforated diaphragm 15 is provided in the deflecting device housing 2 in relation to the inlet perforated diaphragm 7.
• the exit aperture 15 is offset from the entrance aperture 7 transversely to the direction of propagation 14 by the same amount V as the second deflecting mirror 11.
• the exit aperture 15 is displaced by the amount A in the direction of propagation 14 ben, where the amount A is equal to the offset V.
• the exit focus 16 of the monochromator 9 lies in the correctly adjusted state exactly in the opening of the exit pinhole 15.
• the second deflecting mirror 11 which is tilted by 90 ° with respect to the first deflecting mirror 10, directs the output beam 13 of the monochromator 9 onto a third deflecting mirror 17, through which the output beam 13 of the monochromator 9 counteracts the direction of the Offset of the second deflecting mirror 11 with respect to the first deflecting mirror 10 is deflected.
• a fourth deflecting mirror 18 is arranged in the deflecting device housing 2 as an extension of the diverging beam bundle impinging on the first deflecting mirror 10, which coincides in position with the diverging outer beam path 5, and deflects the beam bundle leaving the third deflecting mirror 17 by 90 ° in the direction of propagation 14, so that the light beam leaving the fourth deflecting mirror 18 has the same position as the diverging outer beam path 5.
• Directional housing 2 thus causes on the one hand that the input focus of the monochromator 9 is brought to the location of the intermediate focus 6 of the outer beam path 4, 5 and on the other hand the output focus 16 of the monochromator 9 by mirroring at the deflection mirrors 11, 17 and 18 also at the same Intermediate focus 6 is imaged so that the monochromator arrangement leaves the outer beam path 4, 5 unchanged.
• the input beam 12 of the monochromator 9 first reaches one in the monochromator housing 1.
• Folding mirror 19 inclined by 45 with respect to the longitudinal axis of the centering pin 3.
• the radiation reaches an extra-axial parabolic mirror 20 provided as a collimator mirror, which is fastened in the housing 1 with the aid of an adjustable three-point bearing 21.
• the radiation is collimated by the parabolic mirror 20 to form a parallel beam 22 and then arrives at a grating 23.
• the beam becomes bent towards a plane mirror 26, which is fastened with the aid of an adjustable three-point bearing 27 in the interior of the housing 1.
• the dispersion plane of the grating 23 runs parallel to the plane of the drawing, which runs between the entrance focus 8 and the exit focus 16.
• the plane mirror 26 is essentially from below the incident plane is illuminated and reflects the incident radiation obliquely in the direction above the drawing plane.
• the beam 28 is diffracted a second time on the grating 23 and then focused from the parabolic mirror 20 into the exit focus 16, which is above the drawing plane in FIG. 4, while the entry focus 8 is below the drawing plane in FIG. 4 located.
• FIG. 5 shows a representation that results from FIG. 4 when looking in the direction of an arrow 28 ′.
• the radiation is already diffracted at the first diffraction at the grating 23 in the direction of the parabolic mirror 20.
• the parabolic mirror 20 is adjusted so that the focused radiation cannot fall into the regular exit focus 16 and an incorrect measurement of the laser wavelength is avoided.
• the radiation is focused on the exit focus 16 by aligning the plane mirror 26.
• the input beam 12 and the output beam 13 are only offset transversely to the dispersion plane of the grating 23.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Spectrometry And Color Measurement (AREA)
• Analysing Materials By The Use Of Radiation (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6314619

Family Applications (1)

Country Status (4)

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Citations (4)

Family Cites Families (2)

• 1986
  • 1986-11-24 DE DE19863640044 patent/DE3640044A1/de active Granted
• 1987
  • 1987-11-19 WO PCT/DE1987/000528 patent/WO1988004036A1/de not_active Ceased
  • 1987-11-19 DE DE8787907502T patent/DE3769635D1/de not_active Expired - Lifetime
  • 1987-11-19 EP EP87907502A patent/EP0290529B1/de not_active Expired - Lifetime
  • 1987-11-19 US US07/237,735 patent/US4995725A/en not_active Expired - Fee Related

Patent Citations (4)

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