Alexandrite laser pumped by semiconductor lasers

Abstract

We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl2O4) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the R1 line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

Fibre-coupled red diode-pumped Alexandrite TEM00laser with single and double-pass end-pumping

“…Despite the attractive properties of Alexandrite surprisingly limited investigation has been made of its diode-pumped operation and mostly at very moderate sub-W level [9][10][11][12][13], partially due to the immaturity of the red pumping technology. Recent advance in red diode lasers has been driven by the display industry leading to higher powers with shorter red wavelengths (giving higher absorption in Alexandrite) and longer diode lifetime.…”

Novel laser gain media based on Cr3+-doped mixed borates RX3(BO3)4

“…Novel laser gain media based on Cr 3؉ -doped mixed borates RX 3 This letter discusses the optical properties of Cr 3ϩ ions in mixed borate crystals with the formula RX 3 ͑BO 3 ͒ 4 , where R 3ϩ ϭY 3ϩ or Gd 3ϩ and X 3ϩ ϭAl 3ϩ or Sc 3ϩ . Measurements of the optical absorption spectra have been used to estimate the crystal field strength Dq and the Racah parameters B and C. These quantities confirm that in YAl 3 ͑BO 3 ͒ 4 ͑YAB͒ and GdAl 3 ͑BO 3 ͒ 4 ͑GAB͒Cr 3ϩ ions occupy strong crystal field sites ͓E( 2 E)ϽE( 4 T 2 )͔, whereas in YSc 3 ͑BO 3 ͒ 4 ͑YSB͒ and GdSc 3 ͑BO 3 ͒ 4 ͑GSB͒ the Cr 3ϩ ions occupy weak field sites ͓E( 4 T 2 )ϽE( 2 E)͔.…”

InP/InGaP quantum-dot SESAM mode-locked Alexandrite laser

“…In addition, more efficient mode locking should be possible by designing QD-SESAMs specifically for Alexandrite laser crystal that has a gain peak around 755 nm wavelength [10,11]. Also, low quantum defect of visible diode pumping [13,14] should lead to efficient and powerful ultrafast Alexandrite oscillators that will be very attractive for various applications including nonlinear frequency conversion [39][40][41][42], multiphoton microscopy [43,44], and ultrafast spectroscopy [45].…”

“…On the other hand, Alexandrite (Cr-doped chrysoberyl BeAl2O4) is another example of vibronic laser crystal [10] that has a wide (~100 nm) wavelength tuning range around 750 nm and high thermal conductivity (similar to Ti:sapphire) [11,12]. Its other advantages are highly polarized output radiation and broad absorption bands that can be used for direct pumping with visible laser diodes [13,14]. Unlike Ti:sapphire, Alexandrite can be directly pumped with red laser diodes because its absorption band covers most of the visible spectral range [10,13].…”