1. Copper vapor laser Claire van Lare April 9, 2009

2. Introduction Pulsed laser, pulses 10-80 ns CVL Advantages:
Visible wavelengths
Efficiency of 1-2%
Average power output 100 W or more
Die 10 – 100kHz is de repetition rate. De hoge power output is een gevolg van de hoge efficiency,

3. Set-up T = 1,500 oC 40 Torr Ne 0.1-1.0 Torr Cu-vapor

4. Energy levels Pumping by electron collisions 2 laser transitions
Lower laser levels metastable
Rapid radiative decay from upper level to ground state
Radiation trapping necessary
Radiative decay from u to 0 destroys population inversion, so this should be avoided. To have radiation trapping, a high density of the GS is neceary
W.T. Silvast, Laser Fundamentals,2nd edition, 2008

5. CVL parameters λul: 510.5 nm / 578.2 nm
Δνul: 2.3 * 109 Hz (Doppler broadening)
σul: 8.6 * m2 / 1.25 * m2
Single pass gain: 103–106
2.4 passes (at L=1 m) to reach threshold

6. CVL parameters Output power: 1 MW/pulse; 100 W average
Repetition rates up to 100 kHz
Pump power up to 20 MW/pulse
Mode: high-order multi mode

7. Applications: ablation
Synthesis of multi-wall carbon nanotubes by copper vapor laser
Method: laser ablation
Jamshid Sabbaghzadeh et al., Appl. Phys. A, 2009

8. Applications: ablation
CVL properties:
Emission of visible wavelengths
High power (25 W)
Short pulses (70 ns)
Efficient ablation
Jamshid Sabbaghzadeh et al., Appl. Phys. A, 2009

9. Applications: ablation
Only MWNT formed
SWNT condensation occurs 0.2 ms after ablation
Repetition rate of 10 kHz
SWNT formation prevented by high repetition rate of CVL
Jamshid Sabbaghzadeh et al., Appl. Phys. A, 2009

10. Applications Pump tunable dye lasers High-speed flash photography
Large-image projection television
Material processing