Abstract:
A Littrow-type spectrometer or monochromator (10) using a folded light path to provide a compact optical instrument is disclosed. Light enters the instrument through an inlet aperture on a planar mirror (14). The aperture is located at the focus of a parabolic collimetor-mirror (18). Collimated light reflected by the parabolic mirror is reflected back to the planar mirror, which is positioned at an angle to the collimated light. The light reflected from the planar mirror is directed at a planar grating (20) that produces diffracted light having all the wavelengths input into the system, including light of a selected wavelength, back towards the planar mirror. Light having the selected wavelength is thus caused to fall on the parabolic mirror. The parabolic mirror then focuses the selected wavelength of light ont a light exit aperture that is juxtaposed to the inlet light aperture. The planar grating can be rotatably mounted to scan the input light spectrum.
Abstract:
A Littrow-type spectrometer or monochromator using a folded light path to provide a compact optical instrument is disclosed. Light enters the instrument through an inlet aperture on a planar mirror. The aperture is located at the focus of a parabolic collimetor mirror. Collimated light reflected by the parabolic miror is reflected back to the planar mirror, which is positioned at an angle to the collimated light. The light reflected from the planar mirror is directed at a planar grating that produces diffracted light having all the wavelengths input into the system, including light of a selected wavelength, back towards the planar mirror. Light having the selected wavelength is thus caused to fall on the parabolic mirror. The parabolic mirror then focuses the selected wavelength of light ont a light exit aperture that is juxtaposed to the inlet light aperture. The planar grating can be rotatably mounted to scan the input light spectrum.
Abstract:
A spectrograph with a first concave spectrographic diffraction grating is positioned to receive light from the input light source is configured to provide a diffracted light output dispersing the components of the input light source in a first direction. The dispersion forms the input light into an intermediate spectra. The intermediate spectra is formed in a focal surface by the once diffracted light. A slit is substantially positioned on the focal surface. A second concave diffraction grating is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second direction. The second direction is different from the first direction, the dispersion forming the input light into an output spectra.
Abstract:
A forensic light source and method using an inventive light source comprising a short arc gas vapor discharge lamp is disclosed. A support structure is provided for supporting the source of light. A light guide having first and second ends, is coupled to the source of light at the first end to receive light from the source of light and transmit the light to the second end. The light guide is mounted on the support structure. A filter support member supports a plurality of filters. A portable hand holdable and movable light directing assembly is mounted on the second end of the light guide. The light directing assembly supports the filter support member and provides for movement of the filter support member to a plurality of positions. Each of the positions corresponds to a coupling of a selected one of the filters to the second end, whereby the light emitted from the second end is filtered by the selected filter while the emitted light is directed to various locations through movement of the light directing assembly. A dc power supply has a pulsating dc or constant voltage output.
Abstract:
A forensic light source and method using an inventive light source comprising a short arc gas vapor discharge lamp is disclosed. A support structure is provided for supporting the source of light. A light guide having first and second ends, is coupled to the source of light at the first end to receive light from the source of light and transmit the light to the second end. The light guide is mounted on the support structure. A filter support member supports a plurality of filters. A portable hand holdable and movable light directing assembly is mounted on the second end of the light guide. The light directing assembly supports the filter support member and provides for movement of the filter support member to a plurality of positions. Each of the positions corresponds to a coupling of a selected one of the filters to the second end, whereby the light emitted from the second end is filtered by the selected filter while the emitted light is directed to various locations through movement of the light directing assembly. A dc power supply has a pulsating dc or constant voltage output.
Abstract:
A spectrograph with a first concave spectrographic diffraction grating (16) is positioned to receive light from the input light source (12) is configured to provide a diffracted light output dispersing the components of the input light source in a first direction. The dispersion forms the input light into an intermediate spectrum. The intermediate spectrum is formed in a focal surface by the once diffracted light. A slit (18) is substantially positioned on the focal surface. A second concave diffraction grating (20) is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second direction. The second direction is different from the first direction, the dispersion forming the input light into an output spectrum.
Abstract:
A method for identification of a material by analysis of a sample of the material is disclosed. The method comprises illuminating the sample with a plurality of excitation wavelengths, measuring a plurality of emission wavelengths for each excitation wavelengths to define a measured three-dimensional intensity contour. The values of maxima are located in the three-dimensional intensity contour and are compared to a library of values of known maxima associated with known species. A model of a three-dimensional intensity contour is generated and compared to the measured three-dimensional contour to determine residual errors. A comparison of errors between the generated and measured three-dimensional contours. Error minimization is used to determine the correct model of the three dimensional intensity contour.
Abstract:
A spectrograph with a first concave spectrographic diffraction grating is positioned to receive light from an input light source. The first concave spectrographic diffraction grating is configured to provide a diffracted light output dispersing the components of the input light source in a first dispersion direction with a first angular orientation with respect to the plane of the grating. The dispersion forms the input light into an intermediate spectrum. The intermediate spectrum is formed in a focal surface by the once diffracted light. A slit is substantially positioned on the focal surface. A second concave diffraction grating is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second diffraction direction with a second angular orientation with respect to the plane of the grating. The second dispersion angular orientation is different from the first dispersion angular orientation. The second dispersion forms the input light into an output spectrum.
Abstract:
Spectrofluorometer (10) employing a pair of linear variable spectral filters (14, 18) to produce a three dimensional data output is disclosed. A collimat ed white light source (36) is used that first passes through a first linear variable spectral filter (14), then through a sample (16) where fluorescence occurs, then the resultant light passes through a second linear variable spectral light filter (18) that is oriented at ninety degrees from the first filter (14). The light is then detected by a CCD sensor (20) for conversion into data. This arrangement provides a very simple, rugged and compact instrument that can be used almost anywhere, such as at the scene of a contamination accident.
Abstract:
A spectrograph with a first concave spectrographic diffraction grating is positioned to receive light from the input light source is configured to provide a diffracted light output dispersing the components of the input light source in a first direction. The dispersion forms the input light into an intermediate spectra. The intermediate spectra is formed in a focal surface by the once diffracted light. A slit is substantially positioned on the focal surface. A second concave diffraction grating is positioned to receive once diffracted light from the slit and configured to provide a twice diffracted light output, the second concave diffraction grating dispersing the components of the input light source in a second direction. The second direction is different from the first direction, the dispersion forming the input light into an output spectra.