Optical Science and Engineering ETDs

Publication Date

Fall 12-18-2016

Abstract

Optically-pumped semiconductor disk lasers (SDLs) have received much attention in recent years for a myriad of applications requiring intracavity access, good beam quality, wavelength versatility, and high output powers. The traditional scheme of these lasers feature a semiconductor distributed Bragg reflector (DBR) integrated with the active region, together forming an active mirror in an external free-space cavity. The active mirror component is fabricated by either epitaxial growth or post-growth processing. This places certain restrictions on SDL design, as material system choices become limited. It further viii hinders laser performance with regard to its thermal management and laser bandwidth (tuning range).

This dissertation is concerned with developing SDL’s without the integrated semiconductor DBR in order to mitigate the aforementioned restrictions. We exploit epitaxial lift-off and van der Waals bonding technique to investigate novel DBR-free SDL geometries. Active regions are directly bonded onto various destination substrates, such as right angle prisms forming a total internal reflection (TIR) geometry, or onto optical windows in a transmission arrangement. A quasi-continuous operation is demonstrated using TIR geometry while schemes for continuous-wave operation are proposed in standing wave as well as various monolithic ring cavities. We demonstrate a standing wave monolithic SDL cavity, and analyze its performance.

With the transmission geometry, multi-watt continuous-wave (CW) operation is achieved by employing single-crystal chemical vapor deposition (CVD) diamond windows as heatspreaders: 2 W output power is obtained at 1.15 μm, and more than 6 W is collected at 1 μm. Numerical thermal analysis suggests that DBR-free SDLs outperform traditional SDLs in thermal management when employing two diamond heatspreaders sandwiching the active region. Additionally, significantly broader wavelength tuning range (80 nm) is demonstrated compared with typical SDLs, in good agreement with our extended integrated modal-gain model. Implications of such bandwidth enhancement for mode-locking operation and ultrashort pulse generation is presented.

Finally, we propose a novel gain-embedded meta-mirror (GEMM) concept based on subwavelength grating structures. Our theoretical analysis show that an SDL constructed based on this concept could offer superior thermal management capability with promising potentials for high-power scaling.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Mansoor Sheik-Bahae

Second Committee Member

Jeffrey G. Cederberg

Third Committee Member

Daniel Feezell

Fourth Committee Member

Arash Mafi

Keywords

Semiconductor disk laser; VECSEL; van der Waals bonding; DBR-free; OPSL

Document Type

Dissertation

Language

English

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