Spectrometer Operating Principles

The animation shows how Ocean Optics CCD detector-based Spectrometers operate. Light enters the optical fiber and is efficiently transmitted to the spectrometer. Once in the spectrometer, the divergent light emerging from the optical fiber is collimated by a spherical mirror. The collimated light is diffracted by a plane grating, and the resulting diffracted light is focused by a second spherical mirror. An image of the spectrum is projected onto a linear CCD array, and the data is transferred to a computer through an onboard A/D converter.

Light impinges on photodiodes with the CCD pixels. These reverse-biased photodiodes discharge a capacitor at a rate proportional to the photon flux. When the integration period of the detector is complete, a series of switches closes and transfers the charge to a shift register. After the transfer to the shift register is complete, the switches open and the capacitors attached to the photodiodes are recharged and a new integration period begins. At the same time that light energy is being integrated, the data is read out of the shift register by an A/D converter. The digitized data is then displayed on your computer.

This animation represents CCD operation.