High accuracy for transmittance and reflectance is required for the measurement of optical parts. The SolidSpec-3700/37000DUV have three detectors, which cover the range from ultraviolet to near-infrared. The sensitivity in the near-infrared region is extremely enhanced by using both InGaAs and cooled PbS detectors. Highly accurate and highly sensitive spectra are obtainable from ultraviolet to near-infrared.
Conventional spectrophotometers have used a photomultiplier tube detector for the ultraviolet and visible region and a PbS detector for the near-infrared region. However, neither detector has much sensitivity near the detector switchover, which does not enable high sensitivity measurement in this range. The SolidSpec-3700/3700DUV enable high-sensitivity measurements in the switchover range by using an InGaAs detector.
High Sensitivity Measurement in NIR
The transmittance spectra of a sharp cut filter measured on an InGaAs detector and a PbS detector (conventional spectrophotometer) are shown in the figure below. The SolidSpec-3700/3700DUV demonstrate lower noise between 850 and 1600nm. In the range from 1300 to 1600nm, comparing with the conventional spectrophotometer, noise is reduced to 1/4.
The SolidSpec-3700/3700DUV achieve less than 0.1% noise level under conditions of transmittance less than 1% in the range of 1300 to 1500nm. High sensitivity in this wavelength range makes the SolidSpec-3700/3700DUV a powerful tool to measure low reflection samples, such as anti-reflective coatings or films used in optical communications.
Noise at 1500nm is at the world's lowest level: less than 0.00005Abs (slit width 8nm, RMS) with integrating sphere, and less than 0.00003Abs (slit width 2nm, RMS) with the Direct Detection Unit DDU/DDU-DUV.