Method and apparatus using volume holographic wavelength blockers
First Claim
1. A volume holographic wavelength blocking filter assembly comprising:
- a plurality of reflective volume holographic gratings, each reflective volume holographic grating havinga distinct slant angle;
a distinct grating spacing,wherein the plurality of reflective volume holographic gratings produce a filtered Raman signal when disposed in a path of a Raman signal.
2 Assignments
0 Petitions
Accused Products
Abstract
The invention disclosed here teaches methods to fabricate and utilize a non-dispersive holographic wavelength blocker. The invention enables the observation of the Raman signal near the excitation wavelength (˜9 cm−1) with the compactness of standard thin film/holographic notch filter. The novelty is contacting several individual volume holographic blocking notch filter (VHBF) to form one high optical density blocking filter without creating spurious multiple diffractions that degrade the filter performance. Such ultra-narrow-band VHBF can be used in existing compact Raman instruments and thus will help bring high-end research to a greater number of users at a lower cost.
171 Citations
18 Claims
-
1. A volume holographic wavelength blocking filter assembly comprising:
-
a plurality of reflective volume holographic gratings, each reflective volume holographic grating having a distinct slant angle; a distinct grating spacing, wherein the plurality of reflective volume holographic gratings produce a filtered Raman signal when disposed in a path of a Raman signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. An apparatus for Raman spectroscopy, the apparatus comprising:
-
a laser whose amplified spontaneous emission is filtered by one or more reflective volume holographic grating elements and directed to a physical matter to stimulate Raman scattering, thereby producing a Raman signal; at least one volume holographic wavelength blocking filter assembly disposed in the path of the Raman signal for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal, the volume holographic wavelength blocking filter assembly comprising a plurality of reflective volume holographic gratings, each reflective volume holographic grating having a distinct slant angle and distinct grating spacing; an optical spectrometer disposed in the path of the filtered Raman signal for measuring a spectrum of the Raman signal and for generating a detection signal; and a microprocessor connected to receive the detection signal for determining properties of the physical matter from the detection signal. - View Dependent Claims (13)
-
-
14. An apparatus for Raman spectroscopy, the apparatus comprising:
-
a laser for generating an amplified spontaneous emission; a photosensitive glass wafer comprising; at least one reflective volume holographic grating for filtering the amplified spontaneous emission from the laser directed to a physical matter to stimulate Raman scattering, thereby producing a Raman signal that propagates back through the reflective volume holographic grating, and a plurality of reflective spatially non-overlapping volume holographic gratings, each reflective volume holographic grating having a distinct slant angle and a distinct grating spacing, disposed in a path of the Raman signal for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal; an optical spectrometer disposed in the path of the filtered Raman signal for measuring the spectrum of the Raman signal and for generating a detection signal; and a microprocessor coupled to the optical spectrometer and configured to; receive the detection signal, and determine properties of the physical matter from the detection signal. - View Dependent Claims (15, 16, 17)
-
-
18. An apparatus for Raman spectroscopy, the apparatus comprising:
-
a pump laser for generating amplified stimulated emission light; a photosensitive glass wafer comprising; a doped region surrounded by a pair of reflective high efficiency volume holographic gratings, the pair forming a resonant cavity for receiving light from the pump laser, at least one reflective volume holographic grating for directing the amplified stimulated emission light to a physical matter to stimulate Raman scattering, thereby producing a Raman signal that propagates back through the reflective volume holographic grating, and a plurality of reflective spatially non-overlapping volume holographic gratings, each having a distinct slant angle and a distinct grating spacing, the plurality of reflective spatially non-overlapping volume holographic gratings disposed in the path of the Raman signal for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal; an optical spectrometer disposed in the path of the filtered Raman signal for measuring the spectrum of the Raman signal and for generating a detection signal; and a microprocessor coupled to the optical spectrometer and configured to receive the detection signal for determining properties of the physical matter from the detection signal.
-
Specification