Laser generation in spectrally inhomogeneous condensed media during resonance cross relaxation

L. V. Efimenko, Vladimir S. Mashkevich

Vladimir B. Markov, Tatyana Marusii, M. S. Soskin +1 more

V. O. Kompanets, Yu. A. Matveets, Sergey V. Chekalin

An ultrafast spectrometer with a temporal resolution of 20 fs for studying the polarisation wave interference in condensed matter upon resonance excitation by femtosecond laser pulses is described. The transverse relaxation times T 2 < 20 and 50 fs are measured in optical media with considerably different inhomogeneous broadenings.

Fei Kong, Zhehua Huang, Zhengze Zhao +4 more

Quantum relaxometry based on nitrogen-vacancy (NV) centers in diamond is an easy-to-use technique that detects magnetic noise by measuring the longitudinal relaxation of NV centers. It is favored in chemical and biological applications due to the robustness against imperfect spin control. By tuning the energy level, NV relaxometry can detect magnetic noise generated by other spins and obtain magnetic resonance spectra through cross relaxation. However, the inhomogeneous broadening of NV centers greatly limits the spectral resolution of cross-relaxation spectra. Here we demonstrate a hole-burning technique to remove the inhomogeneous broadening. We utilize a weak pump field to deplete specific NV centers during the relaxation measurement, which contribute a reverse signal in the cross-relaxation spectra with a much narrower linewidth. Our method retains the convenience and sensitivity of NV relaxometry, opening up new avenues for high-resolution magnetic resonance spectroscopy in complex scenarios.

G. B. Altshuler, Vadim S. Ermolaev, K. I. Krylov +1 more

Victor V. Kozlov, Nikolay N. Rosanov

Generation of single-cycle pulses from a laser passively mode locked by the technique of coherent mode locking is theoretically demonstrated for the case when resonant lines of both the gain and absorbing media are inhomogeneously broadened. In contrast to conventional mode-locked lasers, for which the inhomogeneous nature of line broadening sets a severe limitation on their performance, here, the stable single-cycle pulse operation is shown to persist even when the spectral widths of the inhomogeneously broadened lines of the amplifier and the absorber become nearly as wide as the central resonance frequency of their two-level transitions. This study is aimed at showing the potential for application of the coherent-mode-locking technique for quantum-dot lasers, which are typically characterized by a great amount of inhomogeneous broadening.