Abstract
Monolithic nonplanar ring oscillators (NPROs) under an applied magnetic
field can operate unidirectional single-frequency lasing due to the
loss differences among its four eigenpolarizations, where the minimum
was empirically estimated to be 0.01%. However, this value has
never been verified because the applied magnetic field is not
uniformly distributed, making it hard to resolve both theoretically
and experimentally. Here, we propose a method to resolve the applied
magnetic field through an NPRO by combining finite-element analysis
and experimental verification. By introducing the non-uniform magnetic
field information to the eigenpolarization theory, the loss
differences can be calculated by path integration along the optical
path in the NPRO. The critical point, where the bidirectional lasing
is emerging, is identified by the relative amplitude noise (RAN) of
the laser and by the beating signal between the clockwise (CW) and
counterclockwise (CCW) lasing. With this method, we determine that
unidirectional operation is possible with loss differences as low as
0.0001% and 0.0003%, corresponding to two different NPRO
designs with out-of-plane angles of 90° and 45°,
respectively, which increases the precision of the loss differences
for unidirectional single-frequency lasing by more than one order of
magnitude. Our findings will greatly facilitate NPRO laser design with
lowered magnetic field intensity requirements.
Funder
Basic and Applied Basic Research
Foundation of Guangdong Province
National Key Research and Development
Program of China
Subject
Atomic and Molecular Physics, and Optics
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献