Certain configurations are described herein of an optical spectrometer and instruments including an optical spectrometer. In some instances, the optical spectrometer is configured to spatially separate provided wavelengths of light to permit detection or imaging of each provided wavelength of light. Improved sensitivities and detection limits may be achieved using the optical spectrometers described herein.

The present disclosure resides in a spectrometer arrangement including a first dispersing element for spectral separation of radiation in a main dispersion direction, and a second dispersing element for spectral separation of radiation in a cross-dispersion direction, which is at an angle to the main dispersion direction, so that a two-dimensional spectrum is producible. The spectrometer arrangement also includes a collimating optics, which directs collimated radiation to the first and/or second dispersing element, a camera optics, which images a two-dimensional spectrum in an image plane, a two-dimensional detector for detecting the two-dimensional spectrum in the image plane, and an off-axis section of a rotationally symmetric, refractive element, which is arranged between the camera optics and the detector. The present disclosure resides likewise in an optical module comprising such a spectrometer arrangement.

The present disclosure discloses a spectrometer arrangement including an entrance-slit group including a slit wheel and a slit mask for introducing radiation into and for limiting the optical field of the spectrometer arrangement, a first dispersive element for spectrally decomposing the radiation in a main dispersion direction, and a second dispersive element for spectrally decomposing the radiation in a transverse dispersion direction that forms an angle with the main dispersion direction to yield a two-dimensional spectrum. The slit wheel is mounted rotatably about an axis of rotation and has a falcate opening having a width that changes depending on the angle. The slit mask includes an opening that is longer than a largest width of the falcate opening such that radiation radiates through the falcate opening of the slit wheel and the opening of the slit mask. The present disclosure further includes a corresponding method and an optical component group.

In an example, an Echelle grating wavelength division multiplexing (WDM) device includes a first waveguide, a slab waveguide, multiple second waveguides, an Echelle grating, and a metal-filled trench. The first waveguide includes either an input waveguide or an output waveguide. The multiple second waveguides are optically coupled to the first waveguide through the slab waveguide. The multiple second waveguides include multiple output waveguides if the first waveguide includes the input waveguide or multiple input waveguides if the first waveguide includes the output waveguide. The Echelle grating includes multiple grating teeth formed in the slab waveguide. The metal-filled trench forms a mirror at the grating teeth to reflect incident light from the first waveguide toward the multiple second waveguides or from the multiple second waveguides toward the first waveguide.

A two-dimensional spectrometer includes a first mirror, a prism, a diffraction grating, a lens, a second mirror, and a two-dimensional sensor. The first mirror is configured to receive the optical signal from the optical entrance and reflect the optical signal towards the prism. After passing through the prism, the optical signal is provided to the diffraction grating. The diffraction grating diffracts the optical signal so as to generate a diffracted optical signal which is directed back through to prism, wherein the lens configured focuses the diffracted optical signal onto the second mirror. The second mirror reflects the diffracted optical signal back through the lens which focuses the diffracted optical signal onto the two-dimensional sensor. The diffraction grating may be an echelle grating.

A spectrometer with an unobstructed, Schmidt reflector is described. The spectrometer may include a Schmidt corrector and a dispersive element as separate components. Alternatively, the Schmidt corrector and dispersive element may be combined into a single optical component. The spectrometer may further include a field-flattener lens.

Certain aspects, configurations, embodiments, and examples of a spectrometer with a compact design are described. In some implementations, the spectrometers according to the present disclosure may be used for optical emission spectroscopy (OES). The spectrometer architecture and imager described herein allows a single detector, compact, and high-throughput spectrometer. One or more aspects include an Echelle grating in a spectrometer that reuses optical surfaces to separate wavelengths of light. For example, in one or more aspects, a reflective triplet telescope acts as both a collimator and imager. By reusing optical components, the relative size of the spectrometer may be reduced.

A method of optical spectroscopy for analysing a sample using an optical spectrometer is provided. The method comprises obtaining a sample spectrum of the sample using the optical spectrometer and obtaining a blank spectrum using the optical spectrometer. The blank spectrum comprises structured background radiation which is correlated with the sample spectrum. A cross-correlation of the sample spectrum and the blank spectrum is determined. A mapped blank spectrum is generated by mapping the blank spectrum to the sample spectrum based on the cross-correlation, and the mapped blank spectrum is subtracted from the sample spectrum to generate a background corrected sample spectrum.

The present disclosure resides in a spectrometer arrangement including a first dispersing element for spectral separation of radiation in a main dispersion direction, and a second dispersing element for spectral separation of radiation in a cross-dispersion direction, which is at an angle to the main dispersion direction, so that a two-dimensional spectrum is producible. The spectrometer arrangement also includes a collimating optics, which directs collimated radiation to the first and/or second dispersing element, a camera optics, which images a two-dimensional spectrum in an image plane, a two-dimensional detector for detecting the two-dimensional spectrum in the image plane, and an off-axis section of a rotationally symmetric, refractive element, which is arranged between the camera optics and the detector. The present disclosure resides likewise in an optical module comprising such a spectrometer arrangement.

A spectrometer arrangement with two-dimensional spectrum, comprising a first dispersing element for spectral separation of radiation in a main dispersion direction, an imaging optics for imaging the radiation entering into the spectrometer arrangement through an entrance slit in an image plane for producing a two-dimensional spectrum, and a detector array with a two-dimensional arrangement of a plurality of detector elements in the image plane, wherein a reflector, a refractor, and/or a lens array are arranged in the beam path at a location where the dispersed, monochromatic beams are separated from one another, and the reflector, the refractor, and/or the lens array have a surface in the form of a freeform surface, such that area occupied by selected images of the entrance slit in the case of different wavelengths in the image plane is optimized over a selected spectral region of the two-dimensional spectrum.