Sensitivity and spectral control of network lasers

Abstract

Recently, random lasing in complex networks has shown efficient lasing over more than 50 localised modes, promoted by multiple scattering over the underlying graph. If controlled, these network lasers can lead to fast-switching multifunctional light sources with synthesised spectrum. Here, we observe both in experiment and theory high sensitivity of the network laser spectrum to the spatial shape of the pump profile, with some modes for example increasing in intensity by 280% when switching off 7% of the pump beam. We solve the nonlinear equations within the steady state ab-initio laser theory (SALT) approximation over a graph and we show selective lasing of around 90% of the strongest intensity modes, effectively programming the spectrum of the lasing networks. In our experiments with polymer networks, this high sensitivity enables control of the lasing spectrum through non-uniform pump patterns. We propose the underlying complexity of the network modes as the key element behind efficient spectral control opening the way for the development of optical devices with wide impact for on-chip photonics for communication, sensing, and computation.

Optical Gain Switching by Thermo‐Responsive Light‐Emitting Nanofibers through Moisture Sorption Swelling

“…All these properties have been investigated in detail, for both single NFs and planar networks encompassing many fibers. [ 58–60 ]…”

“…All these properties have been investigated in detail, for both single NFs and planar networks encompassing many fibers. [58][59][60] Figure 2a shows the emission spectra from uniaxially aligned PnPrOx/S420 fibers (sample photographed and imaged in its fluorescence in the insets of Figure 2a), upon varying the exci-tation fluence in the interval 0.5-26 mJ cm −2 . These measurements are performed by using a stripe-shaped beam for excitation, with the length of the stripe parallel with the direction of alignment of the NFs (see Experimental Section for more details).…”

Plasma etching for fabrication of complex nanophotonic lasers from bonded InP semiconductor layers

“…As only few network links are pumped, lasing is likely achieved from Fabry-Perot modes that are confined in the waveguides and coupled through scattering at the network's nodes. The occurrence of lasing from only a few links indicates good waveguiding and low scattering losses, and highlights etching of bonded III-V semiconductors as a promising platform for network lasing studies [9,10].…”

“…Through multiple scattering at these nodes, the networks can support random, highly multimode lasing [8,9]. Both of these systems are sensitive to tuning through selective pumping [10][11][12]. Their nonlinear behaviour also shows promise for applications in physical acceleration of machine learning [13,14].…”

Efficient Fluorescence Utilization and Photon Density of States‐Driven Design of Liquid Crystal Lasers

“…This dynamic characteristic allows integration into electro-optic and photonic devices, including tunable filters, lenses, lasers, sensors, gratings, and display systems. [12][13][14][15][16][17][18] Using the inherent advantages of CLC, such as the ability to change the molecular arrangement through external regulation, the chiral photonic band structure and photonic stop band wavelength can be tuned by addressing various external stimuli such as light, [19][20][21][22] temperature, [23][24][25][26] electric field, [10,[27][28][29][30] and magnetic field. [31][32][33] Lin et al [30] have designed an electrically tunable laser (70 nm) composed of a LC-polymer composite with a symmetrical sandwich structure.…”