Oct 2010OptiGrate Corp.Request Info
ORLANDO, Fla., Oct. 1, 2010 — OptiGrate Corp. has launched BragGrate, a line of ultranarrow notch and bandpass filters for Raman spectroscopy applications. The filters have a bandwidth of <10 cm-1, which the company says is about 10 times narrower than other notch and bandpass filters commercially available for these applications.
The filters enable measurements of ultralow frequency Raman bands with standard instruments, rather than with the previous complex, bulky and more expensive tools. Applications include nanotechnology, pharmacology and semiconductor processing.
Stokes and anti-Stokes frequencies can be measured down to 4.5 cm-1 with a set of BragGrate filters using a single-stage spectrometer.
The filters are based on reflecting volume Bragg gratings recorded in proprietary photosensitive glass material. They are formed by holographic techniques in a bulk of glass, with no organic, thermally or optically unstable materials. They exhibit good environmental stability, with no humidity or light-induced degradation, and can withstand temperatures up to 450 °C. The filters are available for a wide range of Raman laser source wavelengths such as 488, 514, 532, 633, 785 and 1064 nm. Custom wavelengths in the range from 450 nm to 2 µm are also available.
The notch filters have an ultranarrow bandstop for Rayleigh light suppression, and they reflect light with bandwidths as narrow as 5 cm-1, while all other wavelengths pass unaffected, with total transmission of 95%. They are stable to light powers of >10 kW, their central wavelengths can be controlled with accuracy of 0.1 to 0.5 nm, and they can be angle-tuned up to 10 nm. Attenuation is from 90 to 99.99%, spectral bandwidth is from 20 pm to 20 nm, operating range is from 350 to 2700 nm, and grating thickness is from 1 to 10 mm. Apertures measure up to 35 × 35 mm.
The bandpass filters are used to clean up laser spectral noise with a bandwidth of 50 pm in the visible and near-infrared regions. They deliver diffraction efficiency of >90% and nearly diffraction-limited beam quality, and have a grating thickness of 0.5 to 5 mm, apertures from 1 to 10 mm and a deflection angle of 5° to 20°. Their spectral bandwidth is <7 cm-1 FWHM.