PGS Optical Bench

The PGS spectrometer series, configured with InGaAs sensors, is designed for SWIR spectroscopy measurements. The special combination of an aspheric collimator lens and a focusing lens enables the use of optimized plane gratings for NIR while retaining good flat-field correction of the spectral imaging.

Central body: A special aluminum alloy with an expansion coefficient of 13E–6, is used for the core housing, around which the aspheric collimator, the blazed grating and the focusing lens are mounted. The input fiber and the detector are firmly affixed to the central body, guaranteeing excellent stability.

Gratings: The plane gratings in the PGS family are either ruled or holographic, optimized for best NIR efficiency. Gratings are dimensioned in such a way that the light from a fiber can be imaged with a NA of up to 0.37.

Input fiber: The light is coupled via a Ø600μm 0.22NA fiber fitted with an internal slit with a height of 500 μm (NIR 1.7) and/or 250 μm (NIR 2.2), matched to the sensors used.

Detector: Cooled and uncooled InGaAs sensors are used for the range up to 1.7 μm in 256 and 512 pixel formats, and modules with extended InGaAs with 256 pixels are used for the range up to 2.2 μm. For the extended InGaAs arrays, an order-sorting filter is applied to the array to suppress the 2^nd diffraction order.

Module Spectral range (nm)

PGS NIR 1.7: 960 to 1,690nm, in 256- and 512-pixel formats, cooled and uncooled.

PGS NIR 2.0-256: 1,340 to 2,000nm

PGS NIR 2.2-256: 1,000 to 2,150nm