Mid-infrared frequency comb from a ring quantum cascade laser

Abstract

The effect of spatial hole burning on mode proliferation has been shown both theoretically and experimentally to be important for frequency comb operation in quantum cascade lasers (QCLs). It is therefore of great interest to investigate the frequency comb operation from integrated ring cavities where this effect is absent. Here we report a mid-infrared quantum cascade laser based on a buried heterostructure ring cavity that exhibits unidirectional lasing with a frequency comb spectrum displaying a predominantly s e c h 2 profile over a bandwidth of ∼ 10 − 1 . A single beat note with 3 dB linewidth of &lt;<!-- 900 H z was observed over the last 85% of the whole current dynamic range. To further verify the frequency comb operation, a multiheterodyne experiment was carried out using a standard Fabry–Pérot QCL comb as a reference laser. This measurement allowed the retrieval of the spectral phases, indicating an operation with strong amplitude modulation.

Mode-locked short pulses from an 8 μm wavelength semiconductor laser

“…In this case, the laser could be operated in a regime where a residual but perfectly linear chirp is accepted in order to optimize for a larger spectral span and more efficient use of the gain. Possible all-solid state solutions could utilize nonlinear effects to produce solitons or solitary structures by pumping a Kerr microresonator 43 or directly by utilizing hybrid mode-locking of the recently reported phase turbulence ring QCLs 44,45 .…”

Parametric resonance of Josephson plasma waves: A theory for optically amplified interlayer superconductivity in YBa2Cu3O6+x

“…Before concluding this paper, we would like to point out that plasmons generated from photoexcited phonons through parametric instability do not radiate out of the sample because of the mismatch of energy and momentum with electromagnetic waves in vacuum. However, they can be made to radiate into the far field, if one adds a metamaterial-type structure on the surface of a sample, which compensates for the momentum mismatch (see, e.g., structures in references [66,67]). By varying the spatial periodicity of such structures, one should be able to enhance emission of Josephson plasmons at different momenta.…”

Поверхностно-Излучающий Квантово-Каскадный Лазер С Кольцевым Резонатором

“…К настоящему моменту успешно реализованы поверхностно-излучающие ККЛ среднего инфракрасного диапазона [5,6], в том числе, в конструкции с кольцевым резонатором [7][8][9][10][11][12][13]. Интерес к исследованиям ККЛ с кольцевым резонатором обусловлен в первую очередь возможностью их применения при детектировании и анализе химических газов [14].…”

“…Более того, малые геометрические размеры позволяют их интегрировать с миниатюрными полыми волноводами (substrate-integrated hollow waveguides), что позволяет создавать системы одновременного детектирования нескольких газов в смеси [15]. Кроме того, в последнее время наблюдается значительный интерес в области исследования частотных гребенок на основе ККЛ с кольцевым резонатором [12,13].…”