| dc.description.abstract | New approaches for generating coherent light are of keen interest to the scientific community due to the increasing demand for unique sources tailored to specific applications. In fields like microscopy, remote sensing, and soft X-ray/XUV lasers this interest is especially pronounced as novel techniques would have a profound impact. Here, we present new methods for generating coherent light by inducing collective coherence in the gain medium. In particular, we demonstrate coherent emission produced through four-wave mixing on a dressed state, stimulated Raman by inducing coherence between two vibrational levels via 2-photon coupling, and finally, a remote atmospheric coherent source via strong-oscillatory superfluorescence in atomic oxygen. Four-wave mixing on a dressed state could be used to generate XUV coherent radiation or remote atmospheric sensing, as it produces both a forward and backward propagating field. We observe this in Rb vapor with emission occurring at detunings of up to 30 nm from the transition. Similarly, 2-photon enhanced stimulated Raman could be implemented for XUV generation as well, due to the asymmetric gain observed on the anti-Stokes emission relative to the Stokes in Methane. It is also a great platform for microscopy as it is background-free unlike other conventional methods like CARS and CSRS. Atmospheric lasing via oxygen is a prime candidate for nextgeneration remote sensing techniques, and here we study its emission mechanisms in depth demonstrating that superfluorescence serves as the main driving process for the observed 845 nm generation. This intense strong-oscillatory emission lends itself for use in coherent Raman techniques. Furthermore, a dual Raman-Brillouin microscope is also presented and demonstrated, which could prove to be a powerful new tool in biomedical and material characterizations applications. | en |
