OSE Dissertation Defense by Mr. Saeid Rostami on Mid-IR Optical Refrigeration and Radiation Balanced Lasers
Posted: March 5, 2020
Date: Friday, March 13, 2020
Time: 10:30 AM to 12:00 PM
Location: PAIS, Room 2540
Map to PAIS:
ADA Accommodations are available. Please contact Doris Williams at email@example.com.
Mr. Saeid Rostami
Ph.D. Candidate, Optical Science and Engineering
Dr. Mansoor Sheik-Bahae (Chair) (UNM)
Dr. Arash Mafi (UNM)
Dr. Ganesh Balakrishnan (UNM)
Dr. Markus Hehlen (LANL)
This dissertation reports the recent advances in mid-IR optical refrigeration and Radiation Balanced Lasers (RBL) in Tm- and Ho-doped crystals. The first demonstration of optical refrigeration in Ho:YLF and Tm:YLF crystals as the promising laser cooling candidates in mid-IR is reported.
Room temperature laser cooling efficiency of the samples at different excitation polarization is measured and their external quantum efficiency and background absorption are extracted. The complete characterization of mid-IR laser cooling samples is obtained by performing detailed low-temperature spectroscopic analysis. Specifically, the Minimum Achievable Temperature (MAT) as a figure of merit for such cooling-grade materials has been estimated, and conditions to achieve laser cooling efficiency enhancement in mid-IR has been investigated.
With the availability of cooling grade Tm- and Ho-doped crystals, the development of mid-IR optical cryocoolers and Radiation Balanced Lasers (RBL) is discussed. By developing a home-made Thulium-doped fiber amplifier (TDFA), seeded with a Continuous Wave Optical Parametric Oscillator (CW-OPO), power cooling experiments on Tm-doped crystals have been performed. Finally, different approaches towards realizing the first mid-IR RBL are discussed. Modeling and optimization of mid-IR RBLs in various Tm- and Ho-doped crystals are studied and conditions to achieve kW-level output intensities are explained.