scholarly journals Organic Diode Laser Dynamics: Rate-Equation Model, Reabsorption, Validation and Threshold Predictions

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 279
Author(s):  
Daan Lenstra ◽  
Alexis Fischer ◽  
Amani Ouirimi ◽  
Alex Chime ◽  
Nixson Loganathan ◽  
...  
Keyword(s):  
Diode Laser ◽  
Short Pulse ◽  
Equation Model ◽  
Rate Equations ◽  
Laser Operation ◽  
Relaxation Oscillations ◽  
Short Pulse Laser ◽  
Laser Dynamics ◽  
Consistent Manner ◽  
Organic Diode

We present and analyze a simple model based on six rate equations for an electrically pumped organic diode laser. The model applies to organic host-guest systems and includes Stoke-shifted reabsorption in a self-consistent manner. With the validated model for the Alq3:DCM host-guest system, we predict the threshold for short-pulse laser operation. We predict laser operation characterized by damped relaxation oscillations in the GHz regime and several orders of magnitude linewidth narrowing. Prospect for CW steady-state laser operation is discussed.

Parametric Study of the Ablation Characteristics of Absorbing Dielectrics by Short Pulse Laser

2000 ◽  
Author(s):  
Samuel George ◽  
Kunal Mitra
Keyword(s):  
Parametric Study ◽  
Short Pulse ◽  
Mathematical Formulation ◽  
Ablation Depth ◽  
Heat Diffusion ◽  
Photon Absorption ◽  
Rate Equations ◽  
Laser Source ◽  
Heat Diffusion Equation ◽  
Short Pulse Laser

Abstract This paper investigates the effect of ablation of absorbing dielectrics by two successive ultra short pulses from an excimer laser source. The numerical model is based on two photon absorption followed by thermal degradation and diffusion. Unlike most previous studies the present formulation considers the transient nature of laser propagation within the medium. Heating of the material is dependent on light absorption by chromophores while ablation occurs through sublimation of the material from the surface. The mathematical formulation takes into consideration the saturation effects within the framework of a three level system of the electronic structure of chromophores. This involves solving a set of coupled rate equations, heat diffusion equation, and the transient radiative transport equation, using Fromm’s scheme. Results for the temperature distribution and ablation depth are obtained for different laser parameters and material properties. Parametric study of the delay time between two successive pulses, laser pulse width, laser fluence, activation energy, and the relaxation time is only performed in this paper for the purpose of brevity. The results obtained by the consideration of the transient radiative transfer equation are compared with the steady state formulation and significant differences are observed in the temperature profiles and the ablation depth.

Silicon Thinning using Ultra-Short Pulse Laser Ablation

2004 ◽  
Author(s):  
F. Beaudoin ◽  
P. Perdu ◽  
C. DeNardi ◽  
R. Desplats ◽  
J. Lopez ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Sample Preparation ◽  
Pulse Laser ◽  
Pulse Laser Ablation ◽  
Short Pulse ◽  
Special Care ◽  
Short Pulse Laser ◽  
Ultra Short Pulse ◽  
Ultra Short Pulse Laser

Abstract Ultra-short pulse laser ablation is applied to IC backside sample preparation. It is contact-less, non-thermal, precise and can ablate the various types of material present in IC packages. This study concerns the optimization of ultra-short pulse laser ablation for silicon thinning. Uncontrolled silicon roughness and poor uniformity of the laser thinned cavity needed to be tackled. Special care is taken to minimize the silicon RMS roughness to less than 1µm. Application to sample preparation of 256Mbit devices is presented.

Chromium oxide dissolution in steels via short pulse laser processing

2013 ◽  
Vol 115 (4) ◽  
pp. 1469-1477 ◽  
Author(s):  
Evgeny Kharanzhevskiy ◽  
Sergey Reshetnikov
Keyword(s):  
Pulse Laser ◽  
Chromium Oxide ◽  
Laser Processing ◽  
Short Pulse ◽  
Oxide Dissolution ◽  
Short Pulse Laser

scholarly journals Experimental study of lateral resistance of bolted joints using Japanese cedar (Cryptomeria japonica) treated with resin impregnation

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Keita Ogawa ◽  
Satoshi Fukuta ◽  
Kenji Kobayashi
Keyword(s):  
Short Pulse ◽  
Japanese Cedar ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Yield Load ◽  
Short Pulse Laser ◽  
Resin Impregnation ◽  
Lateral Resistance ◽  
Ultraviolet Wavelength ◽  
Resistance Performance

Abstract The development of wooden joints possessing high resistance performance has become an important issue for the construction of newer buildings. This study attempts to strengthen the lateral resistance of bolted joints using the previously reported plasticizing technique. This technique consists of two processing stages: incising the surface of the wood using an ultraviolet wavelength short-pulse laser and impregnating the resin into the incised area. This technique makes it possible to plasticize only a local part of the wood surface. Bolted joint specimens were assembled using plasticized wood around the bolt hole, and the lateral tests were conducted. Acrylic monomer and urethane prepolymer were used as the impregnating resins and their incision depths were set as 4 and 10 mm. When the lateral load acted parallel to the grain, changes in the lateral resistance characteristics were observed, especially for the stiffness and yield load. For example, when acryl was used, and the incision depth was 10 mm, an increment of 73% in the yield load was observed, as compared to the non-impregnated specimens. The specimen groups impregnated with acryl exhibited greater changes in their properties than those using urethane. When loaded perpendicular to the grain, an increase in properties were observed; however, these increments were lower than those of the groups loaded parallel to the grain.

scholarly journals Machine learning for multi-dimensional optimisation and predictive visualisation of laser machining

2021 ◽  
Author(s):  
Michael D. T. McDonnell ◽  
Daniel Arnaldo ◽  
Etienne Pelletier ◽  
James A. Grant-Jacob ◽  
Matthew Praeger ◽  
...  
Keyword(s):  
Short Pulse ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Laser Machining ◽  
Laser Materials ◽  
Parameter Optimisation ◽  
Short Pulse Laser ◽  
Alternative Approach ◽  
Highly Nonlinear ◽  
Wide Range

AbstractInteractions between light and matter during short-pulse laser materials processing are highly nonlinear, and hence acutely sensitive to laser parameters such as the pulse energy, repetition rate, and number of pulses used. Due to this complexity, simulation approaches based on calculation of the underlying physical principles can often only provide a qualitative understanding of the inter-relationships between these parameters. An alternative approach such as parameter optimisation, often requires a systematic and hence time-consuming experimental exploration over the available parameter space. Here, we apply neural networks for parameter optimisation and for predictive visualisation of expected outcomes in laser surface texturing with blind vias for tribology control applications. Critically, this method greatly reduces the amount of experimental laser machining data that is needed and associated development time, without negatively impacting accuracy or performance. The techniques presented here could be applied in a wide range of fields and have the potential to significantly reduce the time, and the costs associated with laser process optimisation.

The study of time dependent, broadband X-ray emission from ultra-short pulse laser produced plasmas

1994 ◽  
Author(s):  
Ronnie Shepherd ◽  
Rex Booth ◽  
Dwight Price ◽  
Rosemary Walling ◽  
Richard More ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Short Pulse ◽  
Time Dependent ◽  
X Ray ◽  
Short Pulse Laser ◽  
Ultra Short Pulse ◽  
Ultra Short Pulse Laser
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