Full optical SESAM characterization methods in the 1.9 to 3-µm wavelength regime

Heidrich J., Gaulke M., Alaydin B. Ö. , Golling M., Barh A., Keller U.

Optics Express, cilt.29, sa.5, ss.6647-6656, 2021 (SCI Expanded İndekslerine Giren Dergi) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 29 Konu: 5
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1364/oe.418336
  • Dergi Adı: Optics Express
  • Sayfa Sayıları: ss.6647-6656


© 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementSemiconductor saturable absorber mirrors (SESAMs) are widely used for modelocking of various ultrafast lasers. The growing interest for SESAM-modelocked lasers in the short-wave infrared and mid-infrared regime requires precise characterization of SESAM parameters. Here, we present two SESAM characterization setups for a wavelength range of 1.9 to 3 µm to precisely measure both nonlinear reflectivity and time-resolved recovery dynamics. For the nonlinear reflectivity measurement, a high accuracy (<0.04%) over a wide fluence range (0.1–1500 µJ/cm2) is achieved. Time-resolved pump-probe measurements have a resolution of about 100 fs and a scan range of up to 680 ps. Using the two setups, we have fully characterized three different GaSb-SESAMs at an operation wavelength of 2.05 µm fabricated in the FIRST lab at ETH Zurich. The results show excellent performance suitable for modelocking diode-pumped solid-state and semiconductor disk lasers. We have measured saturation fluences of around 4 µJ/cm2, modulation depths varying from 1% to 2.4%, low non-saturable losses (∼ 0.2%) and sufficiently fast recovery times (< 32 ps). The predicted influence of Auger recombination in the GaSb material system is also investigated.