Dipolar organic materials producing highly efficient laser-like emission
US6839368B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Mar 16, 2001 |
| Grant date | Jan 4, 2005 |
| Priority date | — |
| Expiry date | Jun 4, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/094034
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
High-efficiency laser-like emission at low thresholds in dipolar organic materials upon pulsed optical excitation, without using any external mirrors. Unusually high conversion efficiencies and low thresholds in laser-like emission have been observed in the solutions of organic molecular salts having large dipole moments and specific dye molecules having high photoluminescence efficiencies. Pumped with frequency-doubled pulses from a Nd:YAG laser, conversion efficiencies in the range of 15-40% were achieved without incorporation of external mirrors. The threshold pump energies for such emission have been observed to be low (<8 μJ). The spectrally narrowed output beam was found to have low divergence, high degree of polarization, and pulse-width less than that of the excitation pulses (50 picoseconds). The exceptionally low threshold (<1 μJ) and high energy conversion efficiencies observed in molecular salts have been attributed to the large excited-state dipole moment of these noncentrosymmetric molecules favoring strong cooperative (laser-like) emission in spite of small photoluminescence quantum efficiencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.