Hiroyuki Shiraishi

Lithium potassium borate and lithium rubidium borate: new non-linear optical crystals

The title compounds, LiKB(4)O(7) and LiRbB(4)O(7), are newly developed non-linear optical crystals containing two kinds of anionic groups, namely (B(3)O(8))(7-) and (B(5)O(10))(5-). The (B(3)O(8))(7-) groups form infinite spiral chains parallel to the [100] direction, which are interconnected by sharing O atoms with (B(5)O(10))(5-) groups.

0.43 J, 10 Hz Fourth Harmonic Generation of Nd:YAG Laser Using Large Li2B4O7 Crystals

Using large-sized Li2B4O7 crystals, 0.43 J, 266 nm pulses are obtained from a 10 Hz Nd:YAG laser with a total conversion efficiency of 30.5%. Moreover, 4 W operation for over 15 h is demonstrated.

AlGaAs/GaAs MQW Laser Diode Fabricated on Si Substrates by MOCVD

We report the room-temperature pulsed operation of AlGaAs/GaAs multi-quantum well (MQW) laser diodes (LDs) fabricated on Si substrates by MOCVD. The lowest threshold current obtained in 7 µm-wide oxide stripe MQW LDs was 170 mA at room temperature (at 293 K). The average threshold current and peak wavelength among the tested 60 chips were 324 mA and 864.3 nm, respectively. The maximum differential quantum efficiency was 14.0%.

0.43-J, 10-Hz fourth harmonic generation of Nd:YAG laser using large Li2B4O7 crystals

Using large-sized Li2B4O7 crystals, 0.43-J, 266-nm pulses are obtained from a 10-Hz Nd: YAG laser with a total conversion efficiency of 30.5 %. Moreover, long-term stable, 4-W operation over 15 hour is demonstrated.

Low-Threshold AlGaAs/GaAs MQW Laser Diode Fabricated on Si Substrates by MOCVD

We report the room-temperature pulsed operation of AlGaAs/GaAs multi-quantum well (MQW) laser diodes (LDs) fabricated on Si substrates by metallorganic chemical vapor deposition (MOCVD). The lowest threshold current was 115 mA at room temperature (at 293 K). This is the lowest value of reported laser diodes on Si.

Generation of 0.336-J, 10-Hz, 266-nm pulses from Nd:YAG laser using large Li/sub 2/B/sub 4/O/sub 7/ nonlinear crystals

Summary form only given. We have confirmed the long-term stability of the fourth harmonic generation of a Nd:YAG laser by use of Li/sub 2/B/sub 4/O/sub 7/ crystals with a cascade scheme. We report 336-mJ, 266-nm pulse generation from a 10-Hz, Q-switched Nd:YAG laser with a total conversion efficiency of 23%, and the long-term stability of over 5 hour. This performance is sufficiently good for the pump source of the TW-class UV femtosecond laser system. Additionally this high pulse energy UV laser is attractive for the substitution of the most of industrial KrF excimer lasers used for annealing applications.