Spectrometers include an optical assembly with optical elements arranged to receive light from a light source and direct the light along a light path to a multi-element detector, dispersing light of different wavelengths to different spatial locations on the multi-element detector. The optical assembly includes: (i) a collimator arranged in the light path to receive the light from the light source, the collimator including a mirror having a freeform surface; (2) a dispersive sub-assembly including an echelle grating, the dispersive sub-assembly being arranged in the light path to receive light from the collimator; and (3) a Schmidt telescope arranged in the light path to receive light from the dispersive sub-assembly and focus the light to a field, the multi-element detector being arranged at the field.

An integrated wavelength-selective filter device comprises a first optical element, for directing received radiation into a direction defined by a first angle, and a second optical element being a diffractive element configured for diffracting the directed radiation under a second angle. The second angle is such that for a single reference wavelength the diffracted radiation is directed into a propagation medium for advancing therein towards a predetermined position on the first optical element or on a further optical element for filtering radiation having a wavelength substantially matching the reference wavelength from radiation having a substantially different wavelength. The propagation medium is formed from a material that is different from any material of the substrate of the first and the second optical element.

An integrated wavelength-selective filter device comprises a first optical element, for directing received radiation into a direction defined by a first angle, and a second optical element being a diffractive element configured for diffracting the directed radiation under a second angle. The second angle is such that for a single reference wavelength the diffracted radiation is directed into a propagation medium for advancing therein towards a predetermined position on the first optical element or on a further optical element for filtering radiation having a wavelength substantially matching the reference wavelength from radiation having a substantially different wavelength. The propagation medium is formed from a material that is different from any material of the substrate of the first and the second optical element.

A freeform imaging system with a spectrometer and telescope components optically connected and optimized to increase the spectral and spatial resolution capabilities. Many embodiments of the system are capable of producing a spectral resolution of approximately 1 nm and a spatial resolution less than 30 m such that the imaging system can be used to accurately capture and measure point source plumes of various atmospheric gases including CH.sub.4, CO.sub.2, CO, N.sub.2O, and H.sub.2O.

The present disclosure relates to an atomic absorption spectrometer for analyzing a sample, including a radiation source unit for generating a measuring beam, an atomization unit for atomizing the sample such that the atomized sample is located in a beam path of the measuring beam, and a detecting unit for detecting absorption of the measuring beam. The radiation source unit includes at least one light-emitting diode. According to the present disclosure, the detection unit includes a polychromator arrangement, in particular a high-resolution polychromator arrangement, as a spectrometric arrangement.

A spectrally-resolved Raman water lidar, including: a transmitter unit, a receiver unit, and a data acquisition and control unit. The transmitter unit includes a seeder, a solid Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser, a beam expander, and a first reflecting mirror to emit a 354.8-nm laser beam. The receiver unit includes a telescope, an iris, a collimator, a second reflecting mirror, a first bandpass filter, a beam splitter, a narrow-band interference filter, a third lens, a first detector, a second bandpass filter, a coupler and a home-made dual-grating polychromator to enable simultaneous profiling of backscattered Raman spectrum signals from water vapor, water droplets and ice crystals as well as aerosol fluorescence in the atmosphere. The data acquisition and control unit includes a computer to store the acquired data and guarantee an automatic operation of the lidar system through a time-sequence circuit.

A spectrally-resolved Raman water lidar, including: a transmitter unit, a receiver unit, and a data acquisition and control unit. The transmitter unit includes a seeder, a solid Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser, a beam expander, and a first reflecting mirror to emit a 354.8-nm laser beam. The receiver unit includes a telescope, an iris, a collimator, a second reflecting mirror, a first bandpass filter, a beam splitter, a narrow-band interference filter, a third lens, a first detector, a second bandpass filter, a coupler and a home-made dual-grating polychromator to enable simultaneous profiling of backscattered Raman spectrum signals from water vapor, water droplets and ice crystals as well as aerosol fluorescence in the atmosphere. The data acquisition and control unit includes a computer to store the acquired data and guarantee an automatic operation of the lidar system through a time-sequence circuit.

Spectrometers include an optical assembly with optical elements arranged to receive light from a light source and direct the light along a light path to a multi-element detector, dispersing light of different wavelengths to different spatial locations on the multi-element detector. The optical assembly includes: (i) a collimator arranged in the light path to receive the light from the light source, the collimator including a mirror having a freeform surface; (2) a dispersive sub-assembly including an echelle grating, the dispersive sub-assembly being arranged in the light path to receive light from the collimator; and (3) a Schmidt telescope arranged in the light path to receive light from the dispersive sub-assembly and focus the light to a field, the multi-element detector being arranged at the field.

An integrated wavelength-selective filter device comprises a first optical element, for directing received radiation into a direction defined by a first angle, and a second optical element being a diffractive element configured for diffracting the directed radiation under a second angle. The second angle is such that for a single reference wavelength the diffracted radiation is directed into a propagation medium for advancing therein towards a predetermined position on the first optical element or on a further optical element for filtering radiation having a wavelength substantially matching the reference wavelength from radiation having a substantially different wavelength. The propagation medium is formed from a material that is different from any material of the substrate of the first and the second optical element.

An integrated wavelength-selective filter device comprises a first optical element, for directing received radiation into a direction defined by a first angle, and a second optical element being a diffractive element configured for diffracting the directed radiation under a second angle. The second angle is such that for a single reference wavelength the diffracted radiation is directed into a propagation medium for advancing therein towards a predetermined position on the first optical element or on a further optical element for filtering radiation having a wavelength substantially matching the reference wavelength from radiation having a substantially different wavelength. The propagation medium is formed from a material that is different from any material of the substrate of the first and the second optical element.