Tests and experiments with a femtosecond laser MIRA900 from COHERENT

[femtoman]

The Mira 900 is a Titanium Sapphire tunable femtosecond laser pumped by the Verdi V-10, 10 Watt pump.
The pulsed output has an average power of over 1.6 Watt.
A figure of the Mira, with a block diagram of the main functioning components is shown in figure 1. The Mira uses a passive modelocking scheme; a saturable absorber, and a simple slit to reject continuous wave(CW) operation, and amplify short pulses. Additionally, the Mirra can be configured for femtosecond, or picosecond pulsed operation.

A femtosecond oscillator can be summarized as a « black box » in which there are only optical elements such as mirrors, prisms, lenses and a crystal with 2 extra-ordinary properties.

A continuous laser is injected into this « black box » and a train of femtosecond pulses comes out!

All the dynamics operate around this famous crystal that is titanium-sapphire!It has the power to emit a very large amount of longitudinal frequencies and couple them together by the KERR effect!
This crystal is the « holy grail » of laser physics.

[plazmatron]

The stuff of dreams!

[femtoman]

The MIRA is a femtosecond laser oscillator that produce 6 nJ pules in 100 fs at 78MHz repetition rate.

The RegA 9000 is an amplifier that amplifie 1000 time in energy to 6 uJ 35 fs the pulse coming from the MIRA (show photos) at 150 kHz repetition rate

And the MXR2010 is the most powerfull laser that i have: 1 mJ in 100 fs that is 10 GW per pulse and 1000 pulses per second ! (show photos) pulse compression by filamentation in gas

All this lasers are not easy the make to operate !

Today i start with the MIRA900 .

The MIRA laser was the first femtosecond laser marketed in the 80s. It is very heavy and cluttering however it is ideal for learning how to adjust a femto laser.

[Frank]

Awesome laser!!

[kecked]

The MIRA is a femtosecond laser oscillator that produce 6 nJ pules in 100 fs at 78MHz repetition rate.

The RegA 9000 is an amplifier that amplifie 1000 time in energy to 6 uJ 35 fs the pulse coming from the MIRA (show photos) at 150 kHz repetition rate

And the MXR2010 is the most powerfull laser that i have: 1 mJ in 100 fs that is 10 GW per pulse and 1000 pulses per second ! (show photos) pulse compression by filamentation in gas

All this lasers are not easy the make to operate !

Today i start with the MIRA900 .

The MIRA laser was the first femtosecond laser marketed in the 80s. It is very heavy and cluttering however it is ideal for learning how to adjust a femto laser.

the Mira is easy to run cw……have fun with mode locking. Do you use the pulse picker?

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The MIRA is a femtosecond laser oscillator that produce 6 nJ pules in 100 fs at 78MHz repetition rate.

The RegA 9000 is an amplifier that amplifie 1000 time in energy to 6 uJ 35 fs the pulse coming from the MIRA (show photos) at 150 kHz repetition rate

And the MXR2010 is the most powerfull laser that i have: 1 mJ in 100 fs that is 10 GW per pulse and 1000 pulses per second ! (show photos) pulse compression by filamentation in gas

All this lasers are not easy the make to operate !

Today i start with the MIRA900 .

The MIRA laser was the first femtosecond laser marketed in the 80s. It is very heavy and cluttering however it is ideal for learning how to adjust a femto laser.

the Mira is easy to run cw……have fun with mode locking. Do you use the pulse picker?

[femtoman]

the Mira is easy to run cw……have fun with mode locking. Do you use the pulse picker?

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the Mira is easy to run cw……have fun with mode locking. Do you use the pulse picker?

I hope it won't be too difficult to make it work in pulsed mode. Currently I am studying the 240-page user manual. As soon as I have results I will put pictures!

[kecked]

I hope it won't be too difficult to make it work in pulsed mode. Currently I am studying the 240-page user manual. As soon as I have results I will put pictures!

if it won’t modelock you will see the little knocker arm. Just touch it and sometimes that is enough of an impulse to trigger it.
alignment is easy so is cooling. The pulse picker is just am aom.

getting the pump into the crystal focused correctly is the big challenge. Took me with a tech a full day to get going.
I get about 1-2w in mode lock mode out. Have not measured the pulses power or length yet but it can do some very non linear stuff in water so I’m pretty sure it’s over 15kw and around 100fs.

[mixedgas]

Oxygen adsorption is strong in some parts of the tuning range. You can actually see the dip in lasing power as you pass through an O2 or H2O line. Can also be sensitive to humidity. Leave the ti-saph rod in the mount. Its factory aligned. On "my" Mira long ago, the post-doc had rotated the rod about it's axis, it took me a great deal of time to find the optimum spot over two weeks.

Do not swap optics, make sure they are numbered as you remove them, as they can be tailored to each laser, and often the parts numbers are not in the manual.

The Birefringent tuner has multiple stacked ranges, there is one optimum one, and I'd find it and leave it there.

Not a great idea to change BRF angle relative to the beam.

As Kecked said, once you find the pump sweet spot, and the optimal temperature for the chiller, Ti-Saph wants to lase and lase CW.


Silicon CCD cameras with a 10cm to 2 meter target distance C mount lens, of the kind used for filming cash registers for security, plumbed into a large monitor makes working on MIRA a dream. I did any course alignment with a 785 nm Laser diode. The main ring is easy to align.

Auto-start with the clear bar on the moving actuator open loop galvo, is touchy to adjust, Some times , as Kecked said, its just easy to manually tap so it chops the beam with it's self resonance.

Somewhat dust sensitive, so good to tune it with the cover on.

I have no experience with the built in REGEN.


MIRA IS A FUN LASER !!!

Steve

[femtoman]

Oxygen adsorption is strong in some parts of the tuning range. You can actually see the dip in lasing power as you pass through an O2 or H2O line. Can also be sensitive to humidity. Leave the ti-saph rod in the mount. Its factory aligned. On "my" Mira long ago, the post-doc had rotated the rod about it's axis, it took me a great deal of time to find the optimum spot over two weeks.

Do not swap optics, make sure they are numbered as you remove them, as they can be tailored to each laser, and often the parts numbers are not in the manual.

The Birefringent tuner has multiple stacked ranges, there is one optimum one, and I'd find it and leave it there.

Not a great idea to change BRF angle relative to the beam.

As Kecked said, once you find the pump sweet spot, and the optimal temperature for the chiller, Ti-Saph wants to lase and lase CW.


Silicon CCD cameras with a 10cm to 2 meter target distance C mount lens, of the kind used for filming cash registers for security, plumbed into a large monitor makes working on MIRA a dream. I did any course alignment with a 785 nm Laser diode. The main ring is easy to align.

Auto-start with the clear bar on the moving actuator open loop galvo, is touchy to adjust, Some times , as Kecked said, its just easy to manually tap so it chops the beam with it's self resonance.

Somewhat dust sensitive, so good to tune it with the cover on.

I have no experience with the built in REGEN.


MIRA IS A FUN LASER !!!

Steve

Hello Steve and kecked , thank you for your interesting information about the MIRA;
Actually i have started in CW mode and obtain uniquement the fluorescence at 780 - 800 nm not a cw laser oscillation. It is no easy to start this laser. I make the alignement with 100 mW and pumping at 7W. Please find a picture with the fluorecence mode on the miroir M6. What is the nexte phase ?

http://s848664668.onlinehome.fr/Word...a900-coherent/