Simultaneous retrieval of optical gains, losses, and threshold in active waveguides

Excited states engineering enables efficient near-infrared lasing in nanographenes

“…S13). Complementary, we determined the waveguide losses ( and the net gain coefficient through a recently proposed method, 60 which allows us to simultaneously calculate gain and losses through fits of the ASE and PL spectra. For excitation at either 415 nm or 644 nm, we found a similar gain-dependence on the pump fluence behaviour (Fig.…”

Peri‐Acenoacene for Solution Processed Distributed Feedback Laser: The Effect of 1,2‐Oxaborine Doping

“…Complementary, the net gain ( g net ) variation with the pump fluence and the waveguide propagation losses coefficient (κ) is determined with a recently proposed method that determined them simultaneously through the fitting of the ASE and PL spectra. [ 18 ] Both NGs present similar performances in terms of gain and losses (Figure S5, Supporting Information, and Table 1), with losses being mainly dominated by those of the PS matrix. Moreover, the ASE threshold and gain values of BOTT‐Mes are comparable to those obtained for other NGs [ 5,19 ] and only slightly inferior in performance than those of state of the art organic molecules dispersed in inert matrixes, such as perylenediimides [ 20 ] and carbon‐bridged oligo( p ‐phenylenevinylene)s. [ 21 ] Additionally, the ASE photostability was tested under an uninterrupted ns‐pulsed pump (10 Hz) at four to five times E th‐ASE in ambient conditions.…”

“…Losses and Gain Calculation: Gain and losses were determined from the PL and ASE spectra with a recently developed method. [18,35] This novel method relies on an analytical model for describing the evolution of the ASE intensity with the variation of the excitation. Therefore, it constitutes a generalization of the model used for variable stripe length method.…”

Using the Variable Pump Intensity method to measure optical gains and unveil photophysical and photonic phenomena in active waveguides

“…In particular, the Variable Stripe Length (VSL) method has been profusely used for decades to measure the optical gain in these materials and devices, but experimental and theoretical evidences cast doubts upon its reliability [2]. Seeking to solve those problems, a new formalism to fully characterize the amplification properties of active waveguides based on the most common Variable Pump Intensity (VPI) method has been recently reported by one of us [3]. The analytical expression describing the growth of ASE intensity I ASE (λ,I p ,L) as a function of the wavelength, pump value (I p ; energy/density/intensity/flux/…) and stripe length (L) reads [3]:…”

“…Seeking to solve those problems, a new formalism to fully characterize the amplification properties of active waveguides based on the most common Variable Pump Intensity (VPI) method has been recently reported by one of us [3]. The analytical expression describing the growth of ASE intensity I ASE (λ,I p ,L) as a function of the wavelength, pump value (I p ; energy/density/intensity/flux/…) and stripe length (L) reads [3]:…”