Low noise light source for forensic examination

Apparatus for illuminating a deposition of material and causing it to fluoresce for forensic examination, comprising:

• (a) a light source emitting light having a range of wavelengths;
• (b) a reflective diffraction grating formed in high temperature epoxy and positioned to receive light from said light source;
• (c) a first optical coupler, coupled to said light source, positioned and configured to couple said light to said reflective diffraction grating;
• (d) an exit slit;
• (e) support structure supporting said optical coupler, grating and exit slit to continuously scan through a plurality of selectable relative positions to pass through said slit a desired band of wavelengths of output light from portions of said light reflected by said grating;
• and
• (f) a filter positioned to receive said output light and allow a portion thereof to pass through said filter, said filter having a band characteristic substantially passing said desired band and rejecting light at wavelengths of expected fluorescence of the deposition.

A method of illuminating a deposition of material whose location is unknown for forensic examination, comprising the steps of:

• (a) generating light having a wide range of wavelengths;
• (b) directing said light toward a wavelength selecting member;
• (c) repeatedly scanning said wavelength selecting member through a range of output light wavelengths by adjusting the relative position between an exit port and said wavelength selecting member to result in passage through said exit port of different desired bands of wavelengths of output light from portions of said light output by said wavelength selecting member;
• and
• (d) directing the scanned wavelength output light through a filter, having a pass characteristic which substantially passes the desired bands and blocks light having a wavelength in an expected range of fluorescence of said deposition and directing the scanned filtered wavelength output light toward a plurality of sites in order to detect and illuminate said deposition to be examined.

Apparatus for illuminating a deposition of material and causing it to fluoresce for forensic examination, comprising:

• (a) a light source emitting light having a range of wavelengths;
• (b) a wavelength selecting member formed in high temperature epoxy and positioned to receive light from said light source;
• (c) a first optical coupler, coupled to said light source, positioned and configured to couple said light to said wavelength selecting member;
• (d) an exit port;
• (e) support structure supporting said optical coupler, wavelength selecting member, and exit port to continuously scan through a plurality of selectable relative positions to pass through said port a desired band of wavelengths of output light form portions of said light output by said wavelength selecting member;
• and
• (f) a filter positioned to receive said light from said light source and allow a portion thereof to pass through said filter and fall on said wavelength selecting member, said filter having a pass characteristic substantially passing said desired band and rejecting light at other wavelengths to minimize the generation and transmission of noise in the apparatus.

Apparatus for illuminating a deposition of material and causing it to fluoresce for forensic examination, comprising:

• (a) a light source emitting light having a range of wavelengths;
• (b) a wavelength selecting element formed in light temperature epoxy and positioned to received light from said light source;
• (c) a first optical coupler, coupled to said light source, positioned and configured to couple said light to said wavelength selecting member;
• (d) an exit port;
• (e) support structure movably supporting said optical coupler, wavelength selecting member and exit port to select one of a plurality of selectable relative positions to pass through said port a desired band of wavelengths of output light from portions of said light output by said wavelength selecting member;
• and
• (f) a filter positioned to receive said output light and allow a portion thereof to pass through said filter, said filter having a pass characteristic substantially passing said desired band and rejecting light at wavelengths of expected fluorescence of the deposition.