Continuous-wave stimulated emission and optical amplification in europium (III)-aluminum nanocluster-doped polymeric waveguide

2007 ◽  
Vol 91 (8) ◽  
pp. 081115 ◽  
Author(s):  
K. Yamashita ◽  
H. Taniguchi ◽  
S. Yuyama ◽  
K. Oe ◽  
J. Sun ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Stimulated Emission ◽  
Optical Amplification ◽  
Polymeric Waveguide

GaN-based blue laser diode with 6.0 W of output power under continuous-wave operation at room temperature

2021 ◽  
Vol 42 (11) ◽  
pp. 112801
Author(s):  
Feng Liang ◽  
Degang Zhao ◽  
Zongshun Liu ◽  
Ping Chen ◽  
Jing Yang ◽  
...  
Keyword(s):  
Laser Diode ◽  
Room Temperature ◽  
Continuous Wave ◽  
Chemical Vapor ◽  
Threshold Current ◽  
Stimulated Emission ◽  
Blue Laser ◽  
Organic Chemical ◽  
Blue Laser Diode ◽  
Continuous Wave Operation

Abstract In this work, we reported the room-temperature continuous-wave operation of 6.0 W GaN-based blue laser diode (LD), and its stimulated emission wavelength is around 442 nm. The GaN-based high power blue LD is grown on a c-plane GaN substrate by metal organic chemical vapor deposition (MOCVD), and the width and length of the ridge waveguide structure are 30 and 1200 μm, respectively. The threshold current is about 400 mA, and corresponding threshold current density is 1.1 kA/cm2.

scholarly journals Effect of 405 nm Diode Laser with Varying Irradiation Time on BHK-21 Fibroblast Viability

2019 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Kun Ismiyatin ◽  
Leidy Herlin Rumbiak ◽  
Widya Saraswati ◽  
Sri Kunarti ◽  
Anuj Bhardwaj
Keyword(s):  
Laser Diode ◽  
Irradiation Time ◽  
Control Cell ◽  
Stimulated Emission ◽  
Fibroblast Cells ◽  
Optical Amplification ◽  
Viability Test ◽  
Inhibition Response ◽  
Levene Test ◽  
Radiation Time

Background: Laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation; it can be used for surgery, detoxification, bio stimulation and antibacterial. However, lasers have Biphasic Dose Response (BDR), which is bio stimulation and bio inhibition. To determine if 405 nm laser diode is biocompatible, viability test is necessary before these lasers can be labeled as viable to use in dental therapy. Aim: To prove the variation of radiation time of the 405 nm laser diode radiation can cause bio stimulation and bio inhibition response that affects the viability of BHK-21 fibroblast cells. Method: Viability test was carried out using BHK-21 fibroblast cells which were inserted into 96-well microplate, then radiated with 405 nm laser diode with varying irradiation time of 30s, 60s, 120s, 240s and 480s. After radiation, the cells are then incubated for 24h. Cytotoxicity was observed using MTT assay and ELISA reader. Data was analyzed using the Kolmogorov-Smirnov test, Levene Test, Welch ANOVA, and Tukey HSD. Results: BHK-21 fibroblast cells radiated with 405 nm laser diode with radiation time of 30s, 60s, 120s, and 240s have the same viability as the control cell, while at 480 seconds the viability exceeds that of the control cell. Conclusion: 405 nm laser diode with radiation times of 30s, 60s, 120s, and 240s do not affect the viability of BHK-21 fibroblast cells. Meanwhile, 480s irradiation time of 405 nm laser diode causes bio stimulation response that increases the viability of BHK-21 fibroblast cells.

scholarly journals Amplified Spontaneous Emission and Optical Gain in Organic Single Crystal Quinquethiophene

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 609 ◽  
Author(s):  
Muhammad Zeb ◽  
Muhammad Tahir ◽  
Fida Muhammad ◽  
Suhana Mohd Said ◽  
Mohd Faizul Mohd Sabri ◽  
...  
Keyword(s):  
Single Crystal ◽  
Spontaneous Emission ◽  
Threshold Energy ◽  
Pump Energy ◽  
Optical Gain ◽  
Amplified Spontaneous Emission ◽  
Stimulated Emission ◽  
Excitation Wavelength ◽  
Optical Amplification ◽  
Organic Single Crystal

In this paper, we report optical characteristics of an organic single crystal oligomer 5,5⁗-diphenyl-2,2′:5′,2″:5″,2‴:5‴,2⁗-quinquethiophene (P5T). P5T crystal is a thiophene/phenylene co-oligomer that possesses better charge mobility as well as photoluminescence quantum efficiency (PLQE) as compared to other organic materials. Stimulated emission in P5T is investigated via amplified spontaneous emission (ASE) measurements within broad pump energies ranging from 35.26 to 163.34 µJ/cm2. An Nd-YAG femtosecond-tunable pulsed laser is used as a pump energy source for the ASE measurements of P5T crystals at an excitation wavelength of 445 nm. The ASE spectra exhibit optical amplification in P5T crystals at a 625 nm peak wavelength with a lower threshold energy density (Eth) ≈ 52.64 μJ/cm2. P5T also demonstrates higher optical gain with a value of 72 cm−1, that is calculated by using the variable stripe-length method. The value of PLQE is measured to be 68.24% for P5T. This study proposes potential applications of P5T single crystals in organic solid state lasers, photodetectors, and optical amplifiers.

scholarly journals A Review of the High-Power All-Solid-State Single-Frequency Continuous-Wave Laser

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1426
Author(s):  
Weina Peng ◽  
Pixian Jin ◽  
Fengqin Li ◽  
Jing Su ◽  
Huadong Lu ◽  
...  
Keyword(s):  
Solid State ◽  
High Power ◽  
Continuous Wave ◽  
Beam Quality ◽  
Optical Loss ◽  
Low Noise ◽  
Stimulated Emission ◽  
Single Frequency ◽  
Laser Resonator ◽  
Laser Guidance

High-power all-solid-state single-frequency continuous-wave (CW) lasers have been applied in basic research such as atomic physics, precision measurement, radar and laser guidance, as well as defense and military fields owing to their intrinsic advantages of high beam quality, low noise, narrow linewidth, and high coherence. With the rapid developments of sciences and technologies, the traditional single-frequency lasers cannot meet the development needs of emerging science and technology such as quantum technology, quantum measurement and quantum optics. After long-term efforts and technical research, a novel theory and technology was proposed and developed for improving the whole performance of high-power all-solid-state single-frequency CW lasers, which was implemented by actively introducing a nonlinear optical loss and controlling the stimulated emission rate (SER) in the laser resonator. As a result, the output power, power and frequency stabilities, tuning range and intensity noise of the single-frequency lasers were effectively enhanced.

Photobleaching Reduction in Modulated Super Resolution Microscopy

Microscopy ◽  
2020 ◽  
Author(s):  
Jafar H Ghithan ◽  
Jennifer M Noel ◽  
Thomas J Roussel ◽  
Maureen A McCall ◽  
Bruce W Alphenaar ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Imaging Techniques ◽  
Fluorescence Emission ◽  
Super Resolution ◽  
Optical Power ◽  
Stimulated Emission ◽  
Laser Beams ◽  
Synchronous Detection ◽  
Major Drawback ◽  
Sted Microscopy

Abstract Important breakthroughs in far-field imaging techniques have been made since the first demonstrations of stimulated emission depletion (STED) microscopy. To date, the most straightforward and widespread deployment of STED microscopy has used continuous wave (CW) laser beams for both the excitation and depletion of fluorescence emission. A major drawback of the CW STED imaging technique has been photobleaching effects due to the high optical power needed in the depletion beam to reach sub-diffraction resolution. To overcome this hurdle, we have applied a synchronous detection approach based on modulating the excitation laser beam, while keeping the depletion beam at CW operation, and frequency filtering the collected signal with a lock-in amplifier to record solely the super-resolved fluorescence emission. We demonstrate here that such approach allows an important reduction in the optical power of both laser beams that leads to measurable decreases of photobleaching effects in STED microscopy. We report super-resolution images with relatively low powers for both the excitation and depletion beams. In addition, typical unwanted scattering effects and background signal generated from the depletion beam, which invariably arises from mismatches in refractive-index in the material composing the sample, are largely reduced by using the modulated STED approach. The capability of acquiring super-resolution images with relatively low power is quite relevant for studying a variety of samples, but particularly important for biological species as exemplified in this work.

scholarly journals Nanocrystal Quantum Dots: Building Blocks for Tunable Optical Amplifiers and Lasers

2001 ◽  
Vol 667 ◽  
Author(s):  
Jennifer A. Hollingsworth ◽  
Alexander A. Mikhailovsky ◽  
Anton Malko ◽  
Victor I. Klimov ◽  
Catherine A. Leatherdale ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Optical Amplifiers ◽  
Optical Gain ◽  
Building Blocks ◽  
Stimulated Emission ◽  
Optical Amplification ◽  
Organometallic Reactions ◽  
Wide Range ◽  
Nanocrystal Quantum Dots

ABSTRACTWe study optical processes relevant to optical amplification and lasing in CdSe nanocrystal quantum dots (NQD). NQDs are freestanding nanoparticles prepared using solution-based organometallic reactions originally developed for the Cd chalcogenides, CdS, CdSe and CdTe [J. Am. Chem. Soc. 115, 8706 (1993)]. We investigate NQDs with diameters ranging from 2 to 8 nm. Due to strong quantum confinement, they exhibit size-dependent spectral tunability over an energy range as wide as several hundred meV. We observe a strong effect of the matrix/solvent on optical gain properties of CdSe NQDs. In most of the commonly used solvents (such as hexane and toluene), gain is suppressed due to strong photoinduced absorption associated with carriers trapped at solvent-related interface states. In contrast, matrix-free close packed NQD films (NQD solids) exhibit large optical gain with a magnitude that is sufficiently high for the optical gain to successfully compete with multiparticle Auger recombination [Science 287, 10117 (2000)]. These films exhibit narrowband stimulated emission at both cryogenic and room temperature, and the emission color is tunable with dot size [Science 290, 314 (2000)]. Moreover, the NQD films can be incorporated into microcavities of different geometries (micro-spheres, wires, tubes) that produce lasing in whispering gallery modes. The facile preparation, chemical flexibility and wide-range spectral tunability due to strong quantum confinement are the key advantages that should motivate research into NQD applications in optical amplifiers and lasers.

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