TY  - JOUR
AU  - Matlis, Nicholas
AU  - Olgun, Halil Tarik
AU  - Rentschler, Christian
AU  - Ravi, Koustuban
AU  - Taira, Tokunara
AU  - Ishizuki, Hideka
AU  - Kärtner, Franz
TI  - Scaling narrowband THz generation to large apertures in LiNbO<sub>3</sub> and KTP
JO  - Optics express
VL  - 32
IS  - 19
SN  - 1094-4087
CY  - Washington, DC
PB  - Optica
M1  - PUBDB-2024-04763
SP  - 33875
PY  - 2024
AB  - Millijoule-scale pulses of multicycle terahertz (MC-THz) are increasingly being pursued as drivers for applications requiring high-fields and high spectral brightness. An attractive approach for generating high peak-power MC-THz pulses is nonlinear optical down-conversion of laser pulses in periodically-poled crystals. A principal limitation to the yield, however, is the small (sub-centimeter) apertures of commercially-available crystals which restrict the amount of laser energy that can be used. Here, we explore MC-THz generation by down conversion in two types of large-aperture media for which periodic poling has been achieved in different ways: (1) extension of traditional, voltage-based poling of bulk material to larger (centimeter) scales; and (2) manual poling by assembly of large aperture sub-millimeter thick wafers in alternating orientations. We explore the dependence of efficiency on laser peak fluence and crystal length for both types of media and extend upon previous work with the wafer approach by increasing the number of wafers in the stack, implementing cryogenic cooling and testing an alternate material: potassium titanyl phosphate (KTP). Driving with up to 0.2 J, half-picosecond laser pulses, we obtain conversion efficiencies of up to 0.14
LB  - PUB:(DE-HGF)16
C6  - 39573077
UR  - <Go to ISI:>//WOS:001318649400005
DO  - DOI:10.1364/OE.533354
UR  - https://bib-pubdb1.desy.de/record/610956
ER  -