dyeote
0
- Joined
- Feb 9, 2012
- Messages
- 131
- Points
- 18
I was thinking about N-level laser systems, and whether a diode laser is a '2-level' laser when a question occurred to me: Why must I pump my InGaN bluray diodes with over 4.5V (nearly 6V sometimes) to get a ~3eV photon (405nm)? is there a non-radiative transition in there? or is it a more complicated explanation necessitating a crystal band structure diagram?
Then I thought, even if there is a non-radiative transition in there (which I'm guessing there isn't), the wavelength variance of these diodes under different currents means that this is definitely a complicated band-structure matter :/
From various graphs found on the forum I saw that, with an increasing current, these diodes (PHR, BDR, etc...) increase their pump voltage (more energy per excitation) and increase their wavelength (less energy per emission). Am I correct to infer from this that their pumping band-gap increases and their lasing band-gap decreases ??
Does 'greater current' here directly correlate to a 'greater temperature' of the gain medium?
Responses shedding additional (coherent ) light on the matter would be appreciated, and illustrative graphs doubly so.
Then I thought, even if there is a non-radiative transition in there (which I'm guessing there isn't), the wavelength variance of these diodes under different currents means that this is definitely a complicated band-structure matter :/
From various graphs found on the forum I saw that, with an increasing current, these diodes (PHR, BDR, etc...) increase their pump voltage (more energy per excitation) and increase their wavelength (less energy per emission). Am I correct to infer from this that their pumping band-gap increases and their lasing band-gap decreases ??
Does 'greater current' here directly correlate to a 'greater temperature' of the gain medium?
Responses shedding additional (coherent ) light on the matter would be appreciated, and illustrative graphs doubly so.