Organic materials have broad emission peaks and are ideally suited for the construction of wavelength-tunable micro-nano lasers. However, the emission of organic materials is dominated by the Franck-Condon principle and usually only has higher peaks at short wave 0–1 vibrations. The radiative transition probabilities, while the transitions between other energy levels are significantly suppressed, so organic materials are usually only emitted by the laser at short-wave vibrational bands. Recently, researchers in photochemical laboratories succeeded in breaking through Frank by modulating the vibrational radiative transitions. The Condon principle limits the gain range of organic materials, enabling wavelength-switchable and wide-spectrum tunable organic micro-nano lasers.
First, the researchers used steady-state and transient spectroscopy techniques to elucidate the mechanism of generation of organic vibratory lasers, which revealed the competing behavior between multiple vibrating belt lasers in organic materials and the gain-loss relationship at different vibration bands for laser emission wavelengths. Influence. Based on this, proposed the idea of controlling the relative optical gain intensity at different vibrational bands by temperature-controlled electronic ground state vibration level population, and finally achieving temperature-controlled 0–1 and 0–2 vibrations in organic crystallites. Two-wavelength switchable laser behavior at the peak (Fig. 1). Related research results were published in Nano Lett. 2017, 17, 91-96.
In order to further broaden the emission wavelength of organic micro-nano lasers, the researchers proposed to modulate the electronic vibrational radiation of organic materials by doping optical absorbers to realize the idea of wide-spectrum tuning of organic micro-nano lasers. Using dual-source PVD technology Controllable preparation of organic crystallites with different doping concentrations of absorbers. The introduction of absorbers has succeeded in breaking the limits of the gain range of the Frank-Condon principle and for the first time achieving an organic microcrystalline laser output wavelength in the full spectrum. Adjustments between all vibration bands (0–1, 0–2, 0–3, and 0–4) (Fig. 2). Related research results were published in German Applied Chemistry (Angew. Chem. Int. Ed. 2018, 57, 3108-3112).
Theoretically, the wavelength adjustment mechanism of the above organic micro-nano lasers is applicable to all conjugated organic molecules, which contributes to the improvement of the performance of micro-nano lasers and the extension of functions. More importantly, the tunable laser behavior above breaks through the organic materials. The traditional understanding of the excited state transition and gain process has important guiding significance for the design and development of micro-nano lasers and other optoelectronics components with specific functions.
