Timeplate

Time plate Tripler for ultra fast Lasers
-- simpler and better!

Undisplayed Graphic We now provide a new line of ultrafast triplers for Ti:S lasers. With the addition of the ultrafast fs and ps triplers, Minioptic has become one power source for wavelength conversions.

The new family of high efficiency triplers consists of a complete line of fs and ps triplers for both Ti:S amplifier and Ti:S oscillator. They are manufactured by Minioptic Technology, Inc. based on the new invention of Time PlateÔ (US patent # 5,852,620).

The new ultrafast triplers are the most compact and user friendly, while setting the record of the highest efficiency. The steps of the separation and recombination of the fundamental and SHG beams in other ultrafast triplers are no longer needed and the spatial overlap of the two beams are automatically obtained with the Time PlateÔ design. The smooth time delay control adds more value to the triplers for your application. See the comparison here.

How short the tripling pulse width can be generated by Minioptic’s TP triplers and what is the influence of the Timeplate to the pulse width of the fundament and SHG pulses? Check here for the answer.

Time Plate in the fs Tripler

So far all other fs triplers use a delay line for time compensation. The delay line consists of two beam splitters (or diachronic mirrors), several mirrors, and a translation stage. It works in three steps:

(1) the separation of two laser beams w and 2w;
(2) the two beams traveling through different path and the time delay between them being adjusted by moving the translation stage;
(3) the recombination of the two beams.

The drawbacks of delay line are that it is complicated, expensive, large size, and very difficult to align.

The Time Plate^TM is invented to overcome the drawbacks of delay line. A Time Plate (TP) consists of a specially designed birefringence crystal. After the SHG stage, a time delay between the two beams w and 2w, which are polarized perpendicularly to each other, is generated. The time delay is compensated after the two beams travel through the time plate since they have different refractive indices n_o and n_eff. The delay time is tunable by rotating the angle of the time plate around the z-axis to change the effective index n_eff. One degree rotation changes the time delay about 10 fs for a 2 mm thick calcite crystal. In the fs triplers, there is no beam separation and recombination and the beams wand 2w keep collinear so the spetial overlap are automatically achieved. The better method for spatial and time overlap makes the fs triplers to be very user friendly and more reliable.

Two Tripler Models

There are two tripler models, TPH and TPL for high pulse energy and low pulse energy, respectively. The model TPH is perfect for Ti:S amplifiers. The standard tripler is designed for 1 mJ per pulse energy of kHz Ti:S amplifier systems from Spectra-Physics, Coherent, Clark, and Quantronics. The model for much higher pulse energy is also available, please consult our sales engineers. The model TPL is designed for <5 µJ per pulse energy of mode-locked Ti:S oscillator from Spectra-Physics Tsunami and Coherent Mira and the amplifier from Coherent Rega. The time plate design makes the TPL tripler truly user friendly. The alignment becomes so easy that any one can do it himself.

Specifications for fs standard models:

	Model TPH-fs	Model TPL-fs
SHG pulse energy/average power	>250 mJ	>200 mW
SHG pulse width	<180 fsec	<180 fsec
THG pulse energy/average power	>150 mJ	>100 mW (>50 mW for Rega)
THG pulse width	<300 fsec	<300 fsec

Note: 1. Input for TPH: 1 W, 120 fs, 1 kHz at 800 nm
2. Input for TPL: 1 W, ~76MHz, 100fs at 800 nm

Specifications for ps models:

	Model TPH-ps	Model TPL-ps
SHG pulse energy/average power	>250 mJ	>100 mW
SHG pulse width	1 ps	1 ps
THG pulse energy/average power	>150 mJ	>30 mW
THG pulse width	1 ps	1 ps

Note: 1. Input for TPH: 1 W, 1 ps, 1 kHz at 800 nm
2. Input for TPL: 1 W, ~76MHz, 1 ps at 800 nm

Comparisons:

	TimePlate Technology Minioptic's patent products --- TPH for Ti:S amplifiers, TPL for Ti:S oscillators	Traditional delay line (Inrad Model 5-050 for Ti:S oscillators, Super Optronics/CSK 8315A for Ti:S amplifiers)
Ease of Finding Mixing Signal (e.g. THG)	Easy, because both spatial and temporal overlap are always nearly satisfied, only fine tuning is required.	Hard, one has to adjust wildly to get both spatial and temporal overlap, then fine tuning is possible. Especially, the alignment is very difficult when the THG is lost due to the beam point of the input laser is moved or the tripler is moved.
Efficiency	Fewer optics (1 pcs of TimePlate replaces a traditional delay line of 8 pcs of mirrors), less loss, and better efficiency.	Involves delay line consisting of many more optics (>6 pcs more mirrors), induces more losses. See the comparison figure above (top: TimePlate, below: optical delay line)
Ease Operation and maintainance	Insensitive to vibration, and little external adjustment.	Very sensitive to vibration and external adjustment
Pulse broadening	Too little to be measured, see here for details.	More transmissive optics involved in dichroic separation, means more broadening. No measured data to demonstrate.

Ordering Information

Minioptic Technology, Inc. offers a wide range of crystals and optics to optimize the TP triplers for your application. TPH works for Ti:S amplifier and TPL works for Ti:S oscillator. Both fs and ps operations are available at 680-850 nm and/or 850-1000 nm or 680-1000 nm. Please consult a Minioptic sales engineer with questions on configuration or system efficiencies.

Preliminary test result of TimePlate Ultra-fast tripler: Model TPL

Wavelength (nm)	Input Power (mw)	SHG Power (mw)	THG Power (mw)
740	800	140	89
810	1000	210	126
890	600	78	46
950	350	31	8

Note: Tests are done with a 100fs pulse width Ti:Sapphire oscillator, operating at 80MHz repetition rate.

These test results are done with nearly perfect pump source, efficiency not only depends on Tripler design, but also depend on the beam shape and pulse width characteristics of the pump laser.