Analyzer for coherent radiation
AssigneeThe Perkin-Elmer Corporation
InventorEdward T. Siebert
Life of this patent
Estimating the term…
Abstract
Apparatus for detecting the existance of a source of coherent radiation in the presence of incoherent radiation. A beam splitter splits the radiation into two paths. Means are included in one path for transmitting the incoherent radiation and modulated coherent radiation. The other path effectively transmits only the incoherent radiation. Balancing means are used to balance out the incoherent radiation transmitting only the modulated coherent radiation which is then detected.
Claims20
Apparatus for detecting the existence of a coherent source of radiation in the presence of incoherent ambient radiation comprising:
- aperture means for separating incident radiation into two components to form an etalon path and a reference path;
- an etalon and a first detector disposed in the etalon path;
- a path compensating device and a second detector disposed in the reference path to destroy its coherent modulation characteristics;
- and
- means for balancing the etalon and reference paths for incoherent radiation and for producing an output indicative of the presence of a coherent source.
A method for determining if the coherence length of a beam of light exceeds a preselected threshold value, comprising the steps of:
- projecting the beam through a wedge-shaped optical device, said beam incident over the length of the optical device along the direction of varying thickness thereof, thereby generating a fringe pattern;
- sensing the magnitude of the light exiting the optical device at a plurality of locations simultaneously along the direction of varying thickness of the optical device;
- and
- simultaneously comparing the sensed magnitudes with one another to determine whether the coherence length of the light exceeds the preselected threshold value.
A light beam coherence length discriminator for discriminating between light beams having coherence lengths above and below a preselected threshold length comprising:
- means for generating an optical fringe pattern in response to a beam of light incident thereon;
- sensing means for simultaneously sensing the intensity of the light at a plurality of locations along the generated fringe pattern and producing a plurality of simultaneous output signals indicative of the intensity of the sensed light at the respective locations;
- and
- means for evaluating simultaneously the relative values of the output signals of the sensing means to provide an evaluation of the coherence length of the incident light.
Apparatus for evaluating the coherence length of a light beam comprising:
- a wedge-shaped optical member disposed in the path of the light beam to produce a fringe pattern on the side of the optical member opposite that which intercepts the light beam, the fringe pattern being characteristic of the frequency and spectral bandwidth properties of the incident light;
- a plurality of light detectors disposed at locations of expected maximum and minimum intensities of the fringe pattern for light of a predetermined coherence length, each detector producing an output signal related to the intensity of light at its location;
- means for evaluating the detector output signals relative to each other as an evaluation of the coherence length of the light beam.
Apparatus for discriminating between pulsed beams of light having coherence lengths above and below a preselected coherence length threshold, such light having wavelengths falling within a desired range, comprising:
- optical means for producing an interference fringe pattern from a pulsed beam of light incident thereon;
- light detection means disposed adjacent said optical means and disposed to receive the fringe pattern for producing a set of output signals proportional to the maximum and minimum intensities of the fringe pattern;
- and
- signal processing means connected to said light detection means for comparing such output signals with one another to determine whether the coherence length of the light is above or below the preselected coherence length threshold.
Dependencies are inferred from the claim text.