IPAC2013 - Classification: 07 Accelerator Technology and Main Systems / T25 Lasers

Paper	Title	Page
WEPWA059	Operation of the Drive Laser System for the 2998 MHz NSRRC Photoinjector	2250
	M.C. Chou, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan
	A 266nm UV laser system has been installed as the drive laser of the NSRRC 2998 MHz photo-cathode rf gun. We will report our experiences on using such laser system for rf gun beam test. UV optics for laser beam transport as well as shaping technique we used for emittance preservation will also be presented.

WEPME018	Ytterbium Laser Development of DAW RF Gun for SuperKEKB	2965
	X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida KEK, Ibaraki, Japan
	For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPME021	Development of CO2 Laser Optical Enhancement Cavity for a Laser-Compton X-ray Source	2974
	K. Ando, A. Endo, K. Sakaue, T. Takeichi, M. Washio Waseda University, Tokyo, Japan
	Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization). We have been developing a laser-Compton X-ray source using optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2 laser. We have designed external optical cavity for CO2 laser commercially available optics and verified the enhancement of CO2 laser in external optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 540 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2 laser storage cavity and also some future prospects.

WEPME024	Gaussian Spectrum Fiber Laser Pulses Generated in an All-normal-dispersion Cavity	2983
	Y. You, W.-H. Huang, C.-X. Tang, L.X. Yan TUB, Beijing, People's Republic of China H. Shimizu, J. Urakawa KEK, Ibaraki, Japan
	In this paper, we reported generating a broad bandwidth Gaussian shape spectrum fiber laser pulse directly in an all-normal dispersive cavity. Pulse-shaping is based on spectral filtering. The spectrum has a ~20 nm 20-dB spectrum bandwidth and it is different from the typical spectrum, of steep edge and two spikes. The Gaussian spectrum is preferred since it can be dechirped to transform-limited pulsed duration. The pulse duration corresponds to this kind of spectrum is ~315fs, and pulse energy is up to~9nJ, with a repetition rate of 18.9MHz.

WEPME057	Commission of the Drive Laser System for Advanced Superconducting Test Accelerator	3061
	J. Ruan, M.D. Church, D.R. Edstrom, Jr, T.R. Johnson, J.K. Santucci Fermilab, Batavia, USA
	Currently an advanced superconducting test accelerator (ASTA) is being built at Fermilab. The accelerator will consist of a photo electron gun, injector, ILC-type cryomodules, multiple downstream beam lines for testing cryomodules and carrying advanced accelerator researches. In this paper we will report the commissioning and the drive laser system for this facility. It consists of a fiber laser system properly locked to the master frequency, a regen-amplifier, several power amplifier and final wavelength conversion stage. We will also report the characterization of the whole laser system and the performance of the laser system.

WEPME063	Progress Report on Development of a 5-μm Drive Laser for Dielectric Laser Acceleration	3079
	G. Xu, I. Jovanovic, S.F. Wandel Penn State University, University Park, Pennsylvania, USA E.R. Arab PBPL, Los Angeles, USA P.D. Hoang, P. Musumeci, B.D. O'Shea, J.B. Rosenzweig UCLA, Los Angeles, USA A.Y. Murokh, A.G. Ovodenko RadiaBeam, Santa Monica, USA I. Pogorelsky BNL, Upton, Long Island, New York, USA
	Funding: This work has been sponsored by Defense Advanced Research Project Agency. A simple and robust ultrafast, high-peak-power 5-μm laser source for pumping a dielectric photonic structure for high-gradient electron acceleration has been designed and is being constructed. The use of long wavelength drive lasers can mitigate the problem of dielectric structure breakdown caused by multiphoton ionization. In addition, structure fabrication requirements are relaxed, and greater energy can be stored in the structure. The 5-μm laser source consists of two components: (1) a type-II-beta-barium borate-based 2-μm optical parametric amplifier (OPA) as a pump source, and (2) a type-I-zinc-germaniu-phosphate-based 5-μm OPA to produce mJ-class, <100 fs pulses. Our supercontinuum seeded two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~1.4 mJ with a pulse duration of 42 fs (~6 optical cycles). Carrier-envelope phase (CEP) stabilization is passively established for 2 μm pulses in our OPA design. An modified design of seed pulse generation for the 5-μm OPA based on several cascaded parametric processes can also result in CEP-stable operation for 5-μm amplified pulses.

Paper

Title

Page

Operation of the Drive Laser System for the 2998 MHz NSRRC Photoinjector

2250

M.C. Chou, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

A 266nm UV laser system has been installed as the drive laser of the NSRRC 2998 MHz photo-cathode rf gun. We will report our experiences on using such laser system for rf gun beam test. UV optics for laser beam transport as well as shaping technique we used for emittance preservation will also be presented.

WEPME018

Ytterbium Laser Development of DAW RF Gun for SuperKEKB

2965

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
KEK, Ibaraki, Japan

For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPME021

Development of CO2 Laser Optical Enhancement Cavity for a Laser-Compton X-ray Source

2974

K. Ando, A. Endo, K. Sakaue, T. Takeichi, M. Washio
Waseda University, Tokyo, Japan

Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization).
We have been developing a laser-Compton X-ray source using optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2 laser. We have designed external optical cavity for CO2 laser commercially available optics and verified the enhancement of CO2 laser in external optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 540 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2 laser storage cavity and also some future prospects.

WEPME024

Gaussian Spectrum Fiber Laser Pulses Generated in an All-normal-dispersion Cavity

2983

Y. You, W.-H. Huang, C.-X. Tang, L.X. Yan
TUB, Beijing, People's Republic of China
H. Shimizu, J. Urakawa
KEK, Ibaraki, Japan

In this paper, we reported generating a broad bandwidth Gaussian shape spectrum fiber laser pulse directly in an all-normal dispersive cavity. Pulse-shaping is based on spectral filtering. The spectrum has a ~20 nm 20-dB spectrum bandwidth and it is different from the typical spectrum, of steep edge and two spikes. The Gaussian spectrum is preferred since it can be dechirped to transform-limited pulsed duration. The pulse duration corresponds to this kind of spectrum is ~315fs, and pulse energy is up to~9nJ, with a repetition rate of 18.9MHz.

WEPME057

Commission of the Drive Laser System for Advanced Superconducting Test Accelerator

3061

J. Ruan, M.D. Church, D.R. Edstrom, Jr, T.R. Johnson, J.K. Santucci
Fermilab, Batavia, USA

Currently an advanced superconducting test accelerator (ASTA) is being built at Fermilab. The accelerator will consist of a photo electron gun, injector, ILC-type cryomodules, multiple downstream beam lines for testing cryomodules and carrying advanced accelerator researches. In this paper we will report the commissioning and the drive laser system for this facility. It consists of a fiber laser system properly locked to the master frequency, a regen-amplifier, several power amplifier and final wavelength conversion stage. We will also report the characterization of the whole laser system and the performance of the laser system.

WEPME063

Progress Report on Development of a 5-μm Drive Laser for Dielectric Laser Acceleration

3079

G. Xu, I. Jovanovic, S.F. Wandel
Penn State University, University Park, Pennsylvania, USA
E.R. Arab
PBPL, Los Angeles, USA
P.D. Hoang, P. Musumeci, B.D. O'Shea, J.B. Rosenzweig
UCLA, Los Angeles, USA
A.Y. Murokh, A.G. Ovodenko
RadiaBeam, Santa Monica, USA
I. Pogorelsky
BNL, Upton, Long Island, New York, USA

Funding: This work has been sponsored by Defense Advanced Research Project Agency.
A simple and robust ultrafast, high-peak-power 5-μm laser source for pumping a dielectric photonic structure for high-gradient electron acceleration has been designed and is being constructed. The use of long wavelength drive lasers can mitigate the problem of dielectric structure breakdown caused by multiphoton ionization. In addition, structure fabrication requirements are relaxed, and greater energy can be stored in the structure. The 5-μm laser source consists of two components: (1) a type-II-beta-barium borate-based 2-μm optical parametric amplifier (OPA) as a pump source, and (2) a type-I-zinc-germaniu-phosphate-based 5-μm OPA to produce mJ-class, <100 fs pulses. Our supercontinuum seeded two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~1.4 mJ with a pulse duration of 42 fs (~6 optical cycles). Carrier-envelope phase (CEP) stabilization is passively established for 2 μm pulses in our OPA design. An modified design of seed pulse generation for the 5-μm OPA based on several cascaded parametric processes can also result in CEP-stable operation for 5-μm amplified pulses.