Synchronized tunable mode-locked lasers

Abstract

A synchronized laser system for illuminating a sample with first and second laser light pulses, said system comprising: a trigger, said trigger being operative to issue first and second trigger signals, said first and second trigger signals being emitted at an adjustable frequency with a predetermined delay therebetween; a first tunable mode-locked laser operative for emitting said first laser light pulses in response to receiving a train of said first trigger signals, a first wavelength of said first laser light pulses being dependent on said adjustable frequency in accordance with a first wavelength-frequency relationship; a second tunable mode-locked laser operative for emitting said second laser light pulses in response to receiving a train of said second trigger signals, a second wavelength of said second laser light pulses being dependent on said adjustable frequency in accordance with a second wavelength-frequency relationship; wherein said predetermined delay is such that said first and second laser light pulses are emitted so as to arrive substantially simultaneously in said sample; and said first and second wavelength-frequency relationships are selected to result in a predetermined relationship between said first and second wavelengths at each frequency.

1 . A synchronized laser system for illuminating a sample with first and second laser light pulses having respectively first and second wavelengths, said system comprising:
 a trigger, said trigger being operative to issue first and second trigger signals, said first and second trigger signals being periodic and emitted at a common adjustable frequency with a predetermined delay therebetween, said adjustable frequency being included in a predetermined frequency interval;   a first tunable mode-locked laser operative for emitting said first laser light pulses in response to receiving a first train of said first trigger signals, said first wavelength of said first laser light pulses being dependent on said adjustable frequency in accordance with a first wavelength-frequency relationship, said first tunable mode-locked laser being operative over a first repetition rate range part of said predetermined frequency interval to produce said first laser light with said first wavelength within a first laser tuning range;   a second tunable mode-locked laser operative for emitting said second laser light pulses in response to receiving a second train of said second trigger signals, said second wavelength of said second laser light pulses being dependent on said adjustable frequency in accordance with a second wavelength-frequency relationship, said second tunable mode-locked laser being operative over a second repetition rate range part of said predetermined frequency interval to produce said second laser light with said second wavelength within a second laser tuning range;   wherein
 said predetermined delay is such that said first and second laser light pulses are emitted so as to arrive substantially simultaneously in said sample; and 
 said first and second wavelength-frequency relationships are selected to result in a predetermined relationship between said first and second wavelengths at each adjustable frequency from said predetermined frequency interval at which said first and second repetition rate ranges overlap. 
   
     
     
         2 . A system as defined in  claim 1 , wherein said first and second wavelength-frequency relationships are such that said second wavelength varies less as a function of said adjustable frequency than said first wavelength over said predetermined frequency interval so that over said predetermined frequency interval, said first wavelength varies more than said second wavelength. 
     
     
         3 . A system as defined in  claim 2 , wherein said second wavelength varies at least 100 times more slowly than said first wavelength as as function of said adjustable frequency. 
     
     
         4 . A system as defined in  claim 2 , wherein said sample defines an interaction bandwidth of interest including wavelengths over which a predetermined light-matter interaction occurs, said second laser tuning range being within said interaction bandwidth. 
     
     
         5 . A system as defined in  claim 4 , wherein said sample includes a non-linear material, said predetermined light-matter interaction including a non-linear light-matter interaction occurring in said interaction bandwidth of interest. 
     
     
         6 . A system as defined in  claim 5 , wherein said non-linear material is a frequency doubling material. 
     
     
         7 . A system as defined in  claim 6 , wherein said frequency doubling material is a Lithium Niobate (LiNbO 3 ) crystal, a Barium Borate crystal (BaB 2 O 4 ) or a Potassium Titanyl Phosphate crystal (KTiOPO 4 ). 
     
     
         8 . A system as defined in  claim 2 , further comprising a non-linear material inserted between said second tunable mode-locked laser and said sample. 
     
     
         9 . A system as defined in  claim 8 , wherein said non-linear material is a frequency-doubling material operative for producing light having a third wavelength that is half the first wavelength when illuminated with said first laser light pulses. 
     
     
         10 . A system as defined in  claim 2 , wherein said first repetition rate range is entirely included in said second repetition rate range. 
     
     
         11 . A system as defined in  claim 2 , wherein said first and second wavelength-frequency relationships are such that said first and second wavelengths are respectively a first and a second monotonous function of said adjustable frequency. 
     
     
         12 . A system as defined in  claim 1 , wherein said predetermined frequency interval defines a first interval region and a second interval region, said first and second wavelength-frequency relationships being such that said first and second wavelengths are respectively monotonous functions of said adjustable frequency over each of said first and second interval regions. 
     
     
         13 . A system as defined in  claim 1 , wherein said first tunable mode-locked laser is operative for emitting third laser light pulses in response to receiving said first train of said first trigger signals, a third wavelength of said third laser light pulses being dependent on said adjustable frequency in accordance with a third wavelength-frequency relationship, said first tunable mode-locked laser being operative over said first repetition rate range to also produce said third laser light with said third wavelength within a third laser tuning range. 
     
     
         14 . A system as defined in  claim 12 , wherein said second tunable mode-locked laser is operative for emitting fourth laser light pulses in response to receiving said second train of said second trigger signals, a fourth wavelength of said fourth laser light pulses being dependent on said adjustable frequency in accordance with a fourth wavelength-frequency relationship, said second tunable mode-locked laser being operative over said second repetition rate range to also produce said fourth laser light with said fourth wavelength within a fourth laser tuning range. 
     
     
         15 . A system as defined in  claim 1 , wherein outside of said first and second repetition rate ranges, said first and second tunable mode-locked lasers and are inoperational to produce respectively said first and second laser light pulses.