Switch performance and electronic nature of photonic laser digitizing through thin GaAs films on glass

Abstract

Employing pulsed-laser deposition, we formed thin-film GaAs on glass. Using these films as cross media for continuous laser emissions at 532 nm and 633 nm, we realized extremely straightforward low-power absorptive all-optical logic gates whose switch amplitude can be sensitively controlled with the film thickness. The 532 nm irradiation alters the electronic state of the film with such an impact that transmission digitizing up to 20% was achieved at 633 nm. Pump-probe spectroscopy reveals that the electronic state variation takes place within a few picoseconds. The striking simplicity, the picosecond response time and the undemanding core of the concept make laser crossing very promising for smart applications in digital photonics.

Texture and surface analysis of thin-film GaAs on glass formed by pulsed-laser deposition

“…That peculiar texture, which provides plenty of possibilities to alter the local electronic film state via laser irradiation, explains the readiness of the material to serve for all-optical laser digitizer as we have demonstrated in Refs. [11] and [12].…”

“…Meanwhile, we demonstrated that the photocurrent of PLD GaAs follows the crystalline density of states [10]. Furthermore, we achieved low-power all-optical laser digitizing with the potential to operate in the THz regime with PLD GaAs on glass [11,12]. Film textures, which enable such fast electronic alterations due to laser irradiation are matter of broader interest and it is clearly of importance to investigate the film morphology in detail.…”

Optical gate realization by laser crossing in thin-film semiconductors on glass

“…With fs pump-probe experiments, we established that the absorption increase in GaAs takes place within a few ps. 6 Such an extremely fast response is only possible if the switching phenomenon is based on photo-electronic alterations of the GaAs bandstructure. Therefore, not transferred heat to the film governs the observed phenomenon but electronic properties, such as lifetime, recombination rate, and trap occupancy.…”

Effect of thickness on the microstructural, optoelectronic and morphological properties of electron beam evaporated ZnTe films

“…Utilization of ZnTe thin films in device development were reported by the realization of LED prototypes [11,12], high-efficiency multi-junction solar cells [13], and terahertz (THz) devices [14]. In some reports the concept of laser crossing and all-optical laser transmission digitizing with GaAs [15,16], CdS [17] and InP has been successfully demonstrated [18]. In an earlier report on electron beam evaporated ZnTe films, the optical and dielectric properties were discussed [19].…”