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Open-source photoluminescence system
|By Michigan Tech's Open Sustainability Technology Lab.
Wanted: Students to make a distributed future with solar-powered open-source 3-D printing.
- 1 Introduction
- 2 Design
- 3 Open source PL Design
- 4 See also
- 5 Literature Review
- 6 References
- basic theory - heavily referenced (focus primarily on ingan PL) after initial theory of concept
- equipment list and specs for our ocean optics system
- Design schematic
- pictures of setup
- operation instructions
this section will eventually get ported to its own protocol page.
Open source PL Design
- equipment list and specs
- 3D design schematic - particularly of external case to be printed by reprap
- pictures of setup
- operation instructions
This section is currently being updated...
A photoluminescence sensor for detecting a photoluminescent light from a toluminescent material is disclosed. In a preferred embodiment the photoluminescence sensor comprises: a source of light; a concave mirror having at least one perforation for passing the source light through the at least one perforation; an optical waveguide having proximal and distal ends with the photoluminescent material being disposed at the distal end; an objective for directing the source light into the proximal end of the waveguide; an objective for receiving photoluminescent light and for focusing the photoluminescent light onto the perforated concave mirror; a liquid filter for passing the photoluminescent light reflected from the perforated concave mirror to a detector to detect the photoluminescent light. The sensor can also include a chopper disposed at the output end of the objective for modulating the light source at a select frequency and a lock-in amplifier tuned to measure the output from the detector at the select frequency.
In accordance with the teachings of the present invention, it has been discovered that an optical analysis that is uniquely based on geometrical rather than diffraction considerations, for the purposes of controlling the size of the region from which the photoluminescence is collected, provides an optical system capable of performing photoluminescence microscopy and/or spectroscopy without the disadvantages of the prior art. It is based, in part, on the use of an optical fiber(s) as a field stop within the detection arm(s) of the optical system for coupling the photoluminescence into an optical spectrum analyzer (OSA) and/or photodetector, wherein the diameter and the numerical aperture of the optical fiber are judiciously chosen to limit the field of view, or the region from which the photoluminescence is collected.
Spatially resolved photoluminescence (PL) apparatus is used for the non-destructive characterization of a semiconductor sample. PL excitation from a diode laser is transmitted through a dichroic coupler and, in turn, over a fiber to a fiber collimator wherein the laser light is collimated into a pump beam prior to entering an air path. The air path is composed primarily of an objective lens. The objective lens focuses the pump beam on the sample surface. The photoluminescence signal emitted by the sample travels the same path but in the opposite direction as the pump beam and is collected by the same fiber as a reflected signal. The dichroic fiber coupler is used to separate the return signal from the pump beam with a low insertion loss for each beam. The return PL signal is fed to an optical spectrum analyzer using a single mode fiber connected to the coupler. The sample is placed on a rotational stage capable of x, y and z movement under computer control.
The subject invention relates to the design of a compact imaging spectrometer for use in thin film measurement and general spectroscopic applications. The spectrometer includes only two elements, a rotationally symmetric aspheric reflector and a plane grating. When employed in a pupil centric geometry the spectrometer has no coma or image distortion. Both spherical aberration and astigmatism can be independently corrected. The invention is broadly applicable to the field of optical metrology, particularly optical metrology tools for performing measurements of patterned thin films on semiconductor integrated circuits