OSE Dissertation Defense by Mr. Saeid Rostami on Mid-IR Optical Refrigeration and Radiation Balanced Lasers

Departmental News

Mr. Saeid Rostami

Posted: March 5, 2020

Date: Friday, March 13, 2020 

Time:  10:30 AM to 12:00 PM

Location:  PAIS, Room 2540

Map to PAIS:

PAIS is Building 114
Room 2540 is located on the second floor.  Go up the center steps and turn left. Go to the end of the hall and Room 2540 is located on the left. 

ADA Accommodations are available. Please contact Doris Williams at dorisw@chtm.unm.edu.


Mr. Saeid Rostami
Ph.D. Candidate, Optical Science and Engineering

Committee Members:

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.