IPAC2015 - List of Authors (Chen, Y.)

Paper	Title	Page
TUPMA038	Observation of Significant Quantum Efficiency Enhancement from a Polarized Photocathode with Distributed Brag Reflector	1923
	S. Zhang, M. Poelker, M.L. Stutzman JLab, Newport News, Virginia, USA Y. Chen, A. Moy SVT Associates, Eden Prairie, Minnesota, USA
	Funding: This project was supported by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177. Polarized photocathodes with higher Quantum efficiency (QE) would help to reduce the technological challenge associated with producing polarized beams at milliampere levels, because less laser light would be required, which simplifies photocathode cooling requirements. And for a given amount of available laser power, higher QE would extend the photogun operating lifetime. The distributed Bragg reflector (DBR) concept was proposed to enhance the QE of strained-superlattice photocathodes by increasing the absorption of the incident photons using a Fabry-Perot cavity formed between the front surface of the photocathode and the substrate that includes a DBR, without compromising electron polarization. Here we present recent results showing QE enhancement of a GaAs/GaAsP strained-superlattice photocathode made with a DBR structure. Typically, a GaAs/GaAsP strained-superlattice photocathode without DBR provides a QE of 1%, at a laser wavelength corresponding to peak polarization. In comparison, the GaAs/GaAsP strained-superlattice photocathodes with DBR exhibited an enhancement of over 2 when the incident laser wavelength was tuned to meet the resonant condition for the Fabry-Perot resonator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA038
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Paper

Title

Page

Observation of Significant Quantum Efficiency Enhancement from a Polarized Photocathode with Distributed Brag Reflector

1923

S. Zhang, M. Poelker, M.L. Stutzman
JLab, Newport News, Virginia, USA
Y. Chen, A. Moy
SVT Associates, Eden Prairie, Minnesota, USA

Funding: This project was supported by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177.
Polarized photocathodes with higher Quantum efficiency (QE) would help to reduce the technological challenge associated with producing polarized beams at milliampere levels, because less laser light would be required, which simplifies photocathode cooling requirements. And for a given amount of available laser power, higher QE would extend the photogun operating lifetime. The distributed Bragg reflector (DBR) concept was proposed to enhance the QE of strained-superlattice photocathodes by increasing the absorption of the incident photons using a Fabry-Perot cavity formed between the front surface of the photocathode and the substrate that includes a DBR, without compromising electron polarization. Here we present recent results showing QE enhancement of a GaAs/GaAsP strained-superlattice photocathode made with a DBR structure. Typically, a GaAs/GaAsP strained-superlattice photocathode without DBR provides a QE of 1%, at a laser wavelength corresponding to peak polarization. In comparison, the GaAs/GaAsP strained-superlattice photocathodes with DBR exhibited an enhancement of over 2 when the incident laser wavelength was tuned to meet the resonant condition for the Fabry-Perot resonator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)