Speaker
Description
The physics of solar pumped and radiation-balanced lasers lies in the intersection between solar pumped solid-state materials and the anti-Stokes optical cooling of solids. A solar pumped laser utilizes filtered sunlight directly to pump a gain medium and achieve population inversion for lasing output. Experiments around creating functional solar lasers have been conducted for around two decades now and solar lasers can produce powers in the tens of Watts. Typical solar pumped lasers will utilize a foil to focus around a $1$ $m^2$ area of sunlight onto a rare-earth-doped crystal acting as a gain medium. Depending on the time of day and location on Earth, the solar irradiance is on the order of $600-1000$ $W/m^2$. Furthermore, only a fraction of the solar spectrum can act as a pump for the gain medium. The other important constraint and challenge is to manage the thermal load on the gain medium, knowing that temperature directly affects the lasing threshold and efficiency.
We explore the modelling and feasibility of designing a radiation-balanced solar pumped laser using a common solid-state laser gain media consisting of doped Yttrium Aluminium Garnet (YAG) with Ytterbium (Yb:YAG). Ion doped gain media can be modelled with a fully quantum optical framework because the embedded ions are not interacting with each other and their contributions can be summed. We design the solar pumping and lasing transitions to optimize for additional anti-Stokes cooling transitions to occur efficiently. A fully quantum model helps to elucidate how the microscopic energy exchanges within the gain media, the laser cavity, and the incoherent solar pump are scaled to the macroscopic laser output. Such a design would allow for self-sufficient laser operation in which solar irradiance would both pump and cool the gain media to operate at ideal conditions and maximize laser power output; we aim to demonstrate the feasibility of solar pumped lasers for renewable energy applications.
| Keyword-1 | Solar laser |
|---|---|
| Keyword-2 | Quantum optics |
| Keyword-3 | Solid-state cooling |