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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
- 5.1 Papers/Documents
- 5.1.1 A Low Cost Compact CCD Grating Spectrometer
- 5.1.2 Tolerance design of optical micro-bench by statistical design of experiment
- 5.1.3 Laser photoluminescence spectrometer based on charge-coupled device detection
- 5.1.4 The Spectral Irradiance Monitor: Scientific Requirements, Instrument Design, and Operation Modes
- 5.1.5 Indium Gallium Arsenide Imaging with Smaller Cameras, Higher Resolution Arrays, and Greater Material Sensitivity 
- 5.1.6 XX
- 5.2 Patents/IP
- 5.2.1 Spectrometer - #8,040,707
- 5.2.2 Spectrometer Designs - #7,330,258
- 5.2.3 Compact Imaging Spectrometer - #6,744,505
- 5.2.4 Apparatus for Photoluminescence Microscopy and Spectroscopy - #6,429,968 
- 5.2.5 Fiber-optics based Micro-photoluminescence System - #6,075,592
- 5.2.6 Fiber Optic Photoluminescence Sensor - #5,141,312
- 5.2.7 Full Spectral Range Spectrometer - Appl. #20070019194 
- 5.1 Papers/Documents
- 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...
The authors describe a grating spectrometer consisting of a slit, a transmission holographic grating, a lens, and a CCD (charge coupled device) camera. A frame grabber equipped in a computer digitizes the NTSC signal from the CCD camera. The system is relatively small (12.7 cm×17.8 cm×30.5 cm) and light-weight (5.4 kg). The system will measure the output of modern fluorescent or compact fluorescent lamps more accurately than conventional filter-based photometers.
Design rule of optical micro-bench and tolerance of positional error of components assembled onto the bench are investigated in case of simple linear connections of incoming and outgoing optical fibers with and without ball lenses. Since there are many error variables with wide range of values that affects the optical coupling, the efficient array with reduced number of combinations is generated using statistical design of experiment and coupling efficiencies are calculated. From 3d B point, the tolerance of each position error is determined. For the fiber-to-fiber connection with ball lenses, the longitudinal and lateral positional errors have the strong interaction with each other to the coupling efficiency and thus should be be limited simultaneously.
We describe and characterize a multichannel modular room temperature photoluminescence spectroscopy system. This low cost instrument offers minimization of size and complexity as well as good flexibility and acceptable spectral resolution. The system employs an efficient flexible front end optics and a sensitive spectrometer with a charge-coupled device array detector. The spectrometer has no moving parts and is more robust than a scanning system. The scientific motivation was to enable the photoluminescence study of various silicon photonics structures. Typical applications are presented for SiOx (x<2) films. It is demonstrated that high-quality steady state photoluminescence data with excellent signal to noise enhancement capability can be delivered besides the ability to perform simultaneous multiwavelength measurements in one shot. This instrument is shown to be useful for evaluating semiconductor wafers, including those intended for light emitting structures from silicon-based photonic crystals. The design, construction, calibration, and the unique features of this system are presented, and performance tests of a prototype are discussed.
The Spectral Irradiance Monitor (SIM) is a dual Fèry prism spectrometer that employs 5 detectors per spectrometer channel to cover the wavelength range from 200 to 2700 nm. This instrument is used to monitor solar spectral variability throughout this wavelength region. Two identical, mirror-image, channels are used for redundancy and in-flight measurement of prism degradation. The primary detector for this instrument is an electrical substitution radiometer (ESR) designed to measure power levels ∼1000 times smaller than other radiometers used to measure TSI. The four complementary focal plane photodiodes are used in a fast-scan mode to acquire the solar spectrum, and the ESR calibrates their radiant sensitivity. Wavelength control is achieved by using a closed loop servo system that employs a linear charge coupled device (CCD) in the focal plane. This achieves 0.67 arcsec control of the prism rotation angle; this is equivalent to a wavelength positioning error of δλ/λ = 150 parts per million (ppm). This paper will describe the scientific measurement requirements used for instrument design and implementation, instrument performance, and the in-flight instrument operation modes.
Indium Gallium Arsenide Imaging with Smaller Cameras, Higher Resolution Arrays, and Greater Material Sensitivity 
Indium Gallium Arsenide (InGaAs) photodiode arrays have numerous commercial, industrial, and military applications. During the past 10 years, great strides have been made in the development of these devices starting with simple 256-element linear photodiode arrays and progressing to the large 640 x 512 element area arrays now readily available. Linear arrays are offered with 512 elements on a 25 micron pitch with no defective pixels, and are used in spectroscopic monitors for wavelength division multiplexing (WDM) systems as well as in machine vision applications. A 320 x 240 solid-state array operates at room temperature, which allows development of a camera which is smaller than 25 cm3 in volume, weighs less than 100 g and uses less than 750 mW of power. Two dimensional focal plane arrays and cameras have been manufactured with detectivity, D*, greater than 1014 cm-√Hz/W at room temperature and have demonstrated the ability to image at night. Cameras are also critical tools for the assembly and performance monitoring of optical switches and add-drop multiplexers in the telecommunications industry. These same cameras are used for the inspection of silicon wafers and fine art, laser beam profiling, and metals manufacturing. By varying the Indium content, InGaAs photodiode arrays can be tailored to cover the entire short-wave infrared spectrum from 1.0 micron to 2.5 microns. InGaAs focal plane arrays and cameras sensitive to 2.0 micron wavelength light are now available in 320 x 240 formats.
In the spectrometer 1, a lens portion 3 having a spherical surface 35 on which a spectroscopic portion 4 is provided and a bottom plane 31 in which a light detecting element 5 is disposed, has a side plane 32 substantially perpendicular to the bottom plane 31 and a side plane 34 substantially perpendicular to the bottom plane 31 and the side plane 32. Then, a package 11 that houses a spectroscopy module 10 has side planes 16 and 18 respectively coming into planar-contact with the side planes 32 and 34, and contact portions 22 coming into contact with the spherical surface 35. Therefore, the side planes 32 and 34 of the lens portion 3 are respectively brought into planar-contact with the side planes 16 and 18 of the package 11 while bringing the spherical surface 35 of the lens portion 3 into contact with the contact portions 22 of the package 11, that positions the spectroscopic portion 4 and the light detecting element 5 with respect to a light incident window plate 25 of the package 11.
Various embodiments include spectrometers comprising diffraction gratings monolithically integrated with other optical elements. These optical elements may include slits and mirrors. The mirrors and gratings may be curved. In one embodiment, the mirrors are concave and the grating is convex. The mirrors and grating may be concentric or nearly concentric.
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
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.
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.
A spectrometer is designed capable of effectively covering the full desired spectral range using an array of multiple diffraction gratings arranged in gradually differentiated angles to diffract certain sub-range of photon wavelengths to the target detectors without relying on mechanically changing gratings or use of any moving parts. The optically subdivided spectral analysis results are then electronically integrated to accurately yield the desired full range spectral measurement at a speed compatible to the limit of optical and digital analyzers' speed of the measuring system without manual adjustment and/or mechanical movement delays.
- K. F. Lin and G. Schaefer, “A low cost compact CCD grating spectrometer,” in , Conference Record of the 1993 IEEE Industry Applications Society Annual Meeting, 1993, 1993, pp. 2334–2337 vol.3.
- B. C. Hwang, H. Y. Park, J. Y. Lee, S. G. Park, S. G. Lee, B. H. O, D. S. Choi, and E. H. Lee, “Tolerance design of optical micro-bench by statistical design of experiment,” in CLEO/Pacific Rim 2003 - The 5th Pacific Rim Conference on Lasers and Electro-Optics, 2003, vol. 2.
- O. H. Y. Zalloum, M. Flynn, T. Roschuk, J. Wojcik, E. Irving, and P. Mascher, “Laser photoluminescence spectrometer based on charge-coupled device detection for silicon-based photonics,” Review of Scientific Instruments, vol. 77, no. 2, p. 023907–023907–8, Feb. 2006.
- J. Harder, G. Lawrence, J. Fontenla, G. Rottman, and T. Woods, “The Spectral Irradiance Monitor: Scientific Requirements, Instrument Design, and Operation Modes,” in The Solar Radiation and Climate Experiment (SORCE), G. Rottman, T. Woods, and V. George, Eds. New York, NY: Springer New York, pp. 141–167.
- Martin H. Ettenberg, Marshall J. Cohen, Robert M. Brubaker, Michael J. Lange, Matthew T. O’Grady, and Gregory H. Olsen, “Indium Gallium Arsenide Imaging with Smaller Cameras, Higher Resolution Arrays, and Greater Material Sensitivity.” SPIE, vol. 4721, Proc. of SPIE, p. 4721–26, 2002.
- K. Shibayama, “United States Patent: 8040507 - Spectrometer,” U.S. Patent 8040507 18-Oct-2011.
- C. P. Warren, “United States Patent: 7330258 - Spectrometer designs,” U.S. Patent 7330258 12-Feb-2008.
- D. Y. Wang and D. M. Aikens, “United States Patent: 6744505 - Compact imaging spectrometer,” U.S. Patent 674450501-Jun-2004.
- G. E. Carver, “United States Patent: 6429968 - Apparatus for photoluminescence microscopy and spectroscopy,” U.S. Patent 642996806-Aug-2002.
- S. Banerjee and C. Zah, “United States Patent: 6075592 - Fiber-optics based micro-photoluminescence system,” U.S. Patent 607559213-Jun-2000.
- R. B. Thompson and M. Levine, “United States Patent: 5141312 - Fiber optic photoluminescence sensor,” U.S. Patent 514131225-Aug-1992.
- Chen, Liangyao; Lynch, David W.; and Kao, David T, “United States Patent Application: 0070019194.” [Online].