Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Patent
1998-08-04
2000-12-12
Lee, John R.
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
257 21, 257431, 324 96, H01L 2714, H01L 2940, H01L 31028, G01R 3100
Patent
active
061602523
ABSTRACT:
A photoconductive method or apparatus for measuring high frequency signals using a relatively inexpensive photoconductive material with a relatively long duration or recombination time. The photoconductive method or apparatus utilizes a photoconductive element of photoconductive material such that the duration or recombination time of the photoconductive material is longer than the pulse width of the signal to be measured. As such, the photoconductive element produces a step function response to the signal to be measured rather than a rectangular response with respect to the signal to be measured. The photoconductive element avoids the need to sacrifice measurement sensitivity by introducing defects in the photoconductive material to shorten the recombination time or duration. The measurement bandwidth of the photoconductive element is not limited by the recombination time of the photoconductive material which is mostly dominated by the carrier lifetime. The measurement bandwidth for the photoconductive element is limited by the pulse width of the optical signal driving the photoconductive element which can be very short duration thereby providing improved resolution. As such, the photoconductive element can comprise a cheaper photoconductive material which has a longer duration or recombination time but with a higher sensitivity and improved measurement resolution.
REFERENCES:
patent: 4618819 (1986-10-01), Mourou et al.
patent: 4681449 (1987-07-01), Bloom et al.
patent: 4978910 (1990-12-01), Knox et al.
patent: 5142224 (1992-08-01), Smith et al.
patent: 5844288 (1998-12-01), Mourou et al.
patent: 5864166 (1999-01-01), Stoudt et al.
Matloubian et al., Wide-Band Millimeter Wave Characterization of Sub-0.2 Micrometer Gate-Length AlINAs/GaINAs HEMT's, IEEE Microwave and Guided Wave Letters, 1(2):32-34, Feb. 1991.
Matloubian et al., "Picosecond Optoelectronic Measurement of Parameters and Optical Response of an AlGaAs/GaAs, HBT," IEEE Transactions on Microwave Theory and Techniques, 38(5):683-686, May 1990.
Doany et al., "Carrier Lifetime Versus Ion-Implantation Dose in Solicon on Sapphire," Appl. Phys. Lett., 50(8):460-462, Feb. 23, 1987.
Auston et al., "Picosecond Optoelectronic Detection, Sampling, and Correlation Measurements in Amorphous Semiconductors," Appl. Phys. Lett., 37(4):371-373, Aug. 15, 1980.
Gupta et al., "Subpicosecond Carrier Lifetime in GaAs Grown by Molecular Beam Epitaxy at Low Temperatures," Appl. Phys. Lett., 59(25):3276-3278, Dec. 16, 1991.
Valdmanis et al., "Subpicosecond Electrooptic Sampling: Principles and Applications," IEEE Journal of Quantum Electronics, QE-22(1):69-78, Jan., 1986.
Kim Joung-ho
Mourou Gerard A.
Son Joo-Hiuk
Lee John R.
Regents of the University of Michigan
LandOfFree
Photoconductive element and method for measuring high frequency does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photoconductive element and method for measuring high frequency , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photoconductive element and method for measuring high frequency will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-220230