Accessories for Femtosecond Lasers


Making the best femtosecond lasers even better

  • Wavelength extensions deep UV to mid IR

  • Adjustable repetition rates – single shot to 80 MHz

Coherent femtosecond laser systems are known for delivering an unmatched combination of superior performance, ease of use, high stability, and proven reliability. The performance range of these lasers can be further extended with a help of additional accessories while maintaining all the other important advantages that help maximize your research productivity and data throughput. Second, third, or fourth harmonic generators are available to get your operation into the visible and UV ranges. A range of advanced Optical Parametric Oscillators (OPOs) extend wavelengths into mid-IR region. Pulse pickers will add a repetition rate flexibility to your experiment. 

These accessories are designed to extend the achievable parameter space of Chameleon Discovery NX, Chameleon Ti:Sapphire family and Axon lasers


  • Fluorescence lifetime imaging (FLIM)
  • Transient absorption spectroscopy
  • Fluorescence resonance energy transfer (FRET) imaging
  • Ultrafast Spectroscopy
  • Non-linear optics
  • Material sciences 


Ultrafast Accessories at a Glance

We offer accessories to extend the performance of every Coherent ultrafast oscillator. Most accessories are dedicated to specific lasers to achieve optimized performance. Compatibility table below indicates which accessories are available with the laser you use. 

Accessories Compatibility Table


Available Accessory

Laser System

Harmonic Generation Modules

Pulse PIcker

Select VUE*





Chameleon Discovery NX


Chameleon Ultra II


Chameleon Vision II


Chameleon Vision S





* Select VUE is a pulse picker with integrated SHG module


VUE Harmonics Generation Modules

VUE (Visible and Ultraviolent Extension) is a series of Harmonics Generation modules for generating visible and deep UV wavelengths in an automated, hands-free package. Great care has been applied to the optimization of the nonlinear conversion processes within the modules. For example, all phase matching is seamlessly handled by the VUE. As a result, high conversion efficiencies can be achieved at all input power levels with minimum pulse broadening. Plus the precision opto-mechanical design and built-in walk-off compensators means that the beam position and pointing are optimized no matter how fast or how far the wavelength is tuned. VUE Harmonics feature robust and compact design and deliver excellent beam quality at the output. The module can be controlled via an external control unit or supplied software.  

VUE Harmonic modules are available to generate second (SHG), third (THG) or fourth (FHG) harmonic of the laser wavelength. 


Figure 1

Figure 1: VUE Harmonic Genteration Module


VUE SHG for Chameleon Discovery NX 

The Chameleon Discovery NX is a high-power ultrafast oscillator with the widest tuning range: 660 nm to 1320 nm. The Discovery NX VUE is a dedicated SHG module that takes advantage of this full octave of wavelength range to extend gap-free tuning all the way from 330 nm to 1320 nm, which is ideal for many ultrafast spectroscopy applications. Excellent beam quality is maintained for microscopy applications such as FLIM and FRET. Phase matching is also maintained automatically through communication between VUE SHG, and the GUI of Discovery NX; no user intervention, adjustment or tweaking is required from this closed box unit. The Discovery NX VUE is also compatible with the Total Power Control (TPC) option for Chameleon Discovery which enables fast and precise power modulation at all wavelengths.

The forth harmonic generation (FHG) module options are available upon request and allows a gap-free wavelength extension to 250nm.  


Figure 2
Figure 3

Figure 2: Typical performance curves for Discovery lasers combined with the VUE SHG.




Chameleon Discovery VUE SHG

Tuning Range (nm)

330 to 660

Conversion Efficiency (%)1


Mechanical Parameters 

Dimensions (L x W x H)

385 x 286 x 207 mm (15.2 x 11.3 x 8.1 in.)

1. At peak of tuning range.


VUE Harmonics for Chameleon Ti:Sapphire Lasers

Chameleon VUE is a series of Harmonics Generation options for generating visible and deep UV wavelengths in an automated, hands-free package. Chameleon VUE SHG is a second harmonic generation module, which can cover 340 nm to 540 nm. Chameleon VUE THG is a third harmonic generation module that also delivers SHG output, resulting in complete wavelength coverage from 227 nm to 540 nm. Even shorter wavelengths of 210 to 230 nm can be achieved by using the VUE FHG fourth harmonic module. All modules are dedicated for use with our tunable Chameleon Ti:Sapphire lasers and emphasize both performance and ease of use. Careful optimization of the nonlinear conversion optics within the modules results in high conversion efficiencies with minimum pulse broadening. Just as important, these VUE modules communicate with the Chameleon laser automatically, enabling push-button software control of wavelength tuning with automated phase-matching maintained throughout.

Figure 4
Figure 50

Figure 3: Typical performance curves for the Chameleon VUE SHG and THG modules.




Chameleon VUE SHG

Chameleon VUE THG

Chameleon VUE FHG 

Chameleon Ultra II Pump

Tuning Range (nm)

340 to 540

227 to 5401

210 to 230 

Conversion Efficiency (%)2




Chameleon Vision II Pump

Tuning Range (nm)

340 to 540

227 to 5401

Conversion Efficiency (%)2




Chameleon Vision S Pump

Tuning Range (nm)

345 to 520

230 to 3451

Conversion Efficiency (%)2




Mechanical Parameters

Dimensions (L x W x H)

385 x 286 x 207 mm  (15.2 x 11.3 x 8.1 in.)

1. VUE THG also includes SHG stage for access to SHG wavelengths, typical efficiency 20% at peak.
2. At peak of tuning range.


Figure 6

Figure 4: Wavelength coverage examples of Chameleon Discovery NX and Ultra II lasers when used in combination with harmonic generators. 

*FHG modules are available upon request.   


VUE SHG for Axon

Our fixed wavelength femtosecond system Axon can be combined with dedicated second harmonic SHG module for operation at visible or UV wavelengths. The rugged simplicity and ease of operation of these modules provides high conversion efficiency and stable beam pointing. No tweaking or internal alignment is required with these turnkey modules. VUE SHG modules are also compatible with the Total Power Control (TPC) option for Axon lasers which enables fast and precise power modulation with no need for external modulators. Third harmonic THG solutions are also available with our fixed wavelength laser sources upon request. 




Axon 780

Wavelength (nm)


Conversion Efficiency (%)


Axon 920

Wavelength (nm)


Conversion Efficiency (%)


Axon 1064

Wavelength (nm)


Conversion Efficiency (%)


Mechanical Parameters

Dimensions (L x W x H)

385 x 286 x 207 mm (15.2 x 11.3 x 8.1 in.)


Pulse Pickers

Whenever you are looking to reduce the repetition rate of your femtosecond laser, this can be achieved by using an external pulse picker. Pulse Select pulse pickers are based on acousto-optic modulator (AOM) technology and feature low dispersion design with the use of reflective optics for most of the optical path, ensuring minimal pulse stretching.

Pulse Select provides a wide range of pulse picking frequencies - from single pulse to frep/2, i.e., 40 MHz. The repetition rate of the output pulses can be controlled by using an internal frequency selector, or synchronized to the laser repetition rate or an external trigger signal. A wide wavelength coverage is available: our standard Broadband pulse picker model provides efficient operation from 500 nm to 1600 nm and is ideal for use with our broadly tunable Chameleon Discovery NX and our Ti:Sapphire lasers or associated OPOs. The Dualband model covers wavelengths 340 nm to 540 nm and 680 nm to 1080 nm, making it an ideal pulse picker for a Ti:Sapphire laser and its second harmonic wavelengths. Both Broadband and Dualband models are operated with single optics sets, simplifying their use. 

Double stage pulse pickers are also available upon request. These can be configured to be used in Series (two Bragg cells in sequence) for ultra-high contrast ratio (200,000:1 for non-adjacent pulses) or in Parallel configuration for simultaneous pulse picking from two synchronized sources such as a laser oscillator and OPO.


Pulse Select Advantages

  • Low dispersion – supports pulses as short as < 20 fs
  • Synchronized to laser seed with internal trigger
  • Pulse picking frep/260,000 to frep/2 
  • External trigger operation – single shot to 3 MHz 


Figure 7





Wavelength Range (nm)

500 - 1600

340 – 540 and 680 – 1080 

Max input power (W)

5 (at 800 nm)

Input frequency (frep, MHz)


Output Repetition Rate – internal trigger

frep/260,000 to frep/2

Output Repetition Rate – external trigger

Single-shot to 3 MHz

Diffraction efficiency

(at 800 nm, frep/20, %)


Contrast Ratio 

(at 800 nm, frep/20)

>75:1 for adjacent pulses

>500:1 for non-adjacent pulses

Head Mechanical Parameters

Dimensions (L x W x H)

385 x 286 x 224 mm  (15.2 x 11.3 x 8.8 in.)


Select VUE – Combined SHG and Pulse Picking

Select VUE is a compact module that integrates the functionality of both a SHG harmonic module and a pulse picker in a single-box solution. Optimized for use with our tunable Chameleon 80 MHz lasers, the optics in Select Vue are carefully chosen to minimize pulse dispersion. The flexible Select VUE includes three output ports that provide separate access to the undiffracted beam (fundamental 80MHz), the picked fundamental wavelength, and the picked SHG wavelength, further maximizing the value of this unique accessory.


Select VUE Advantages

  • Compact single box-solution
  • Low dispersion design
  • Picker+SHG, or Picker-only operation.
  • Broadband operation
  • Single-shot up to 40 MHz
  • Motorized operation


Figure 8



Select VUE

Input specification

Input Wavelength Range (nm)

660 – 1320 (Chameleon Discovery NX)

680 – 1080 (Chameleon Ultra II)

Input Repetition Rate (MHz)


Input average power (W)


Input polarization

Horizontal, linear

Output Specifications: Picked SHG

Wavelength range (nm)

330 – 660 (Chameleon Discovery NX)

340 – 540 (Chameleon Ultra II)

Contrast Ratio1

> 3000:1 (adjacent pulses)

> 100000:1 (non-adjacent pulses)

Efficiency (%)1, 2


Repetition Rate (MHz)

Single shot to 40

Output Polarization

Vertical, linear

Output Specifications: Picked Fundamental

Wavelength range 

660 – 1320 (Chameleon Discovery NX)

680 – 1080 (Chameleon Ultra II)

Contrast Ratio3

> 75:1 (adjacent pulses)

> 500:1 (non-adjacent pulses)

Efficiency (%)3


Repetition rate

Single shot to 40 MHz

Output polarization

Horizontal, linear

Mechanical Parameters

Dimensions (L x W x H)

587 x 406 x 189...221 mm (23.1 x 16 x 7.4...8.7 in.)

1. Applicable at 400nm and f/20
2. Combined picker+SHG efficiency
3. Applicable at 800nm and f/20


Figure 9
Figure 10


Optical Parametric Oscillators (OPOs)

An Optical Parametric Oscillator (OPO) is a nonlinear optical device that allows the extension of the pump laser wavelength into the IR region with access to both signal and idler beams. These can enable new wavelengths for nonlinear, multimodal imaging, or provide a wide operational window in laser spectroscopy applications. Coherent offers a wide selection of femtosecond OPOs that can be used with Chameleon Discovery NX, Chameleon Ti:Sapphire systems, or Axon lasers serving as pump sources. All our OPOs are designed to be fully automated and allow convenient hands-free operation.   

Chameleon Compact OPO (C-OPO) provides wavelength extension up to 1600 nm giving a combined gap-free tuning range of 680 – 1600 nm when used with Chameleon Ultra II or Vision II laser as a pump source. An idler option is also available to access wavelengths from 1750 – 4000 nm. The pump laser wavelength and OPO wavelength can be tuned independently, enabling two-color imaging or pump/probe applications.   

Chameleon Compact OPO-VIS (C-OPO-VIS) is a unique wavelength extension module that provides independent pump and signal tuning and also adds visible and UV wavelengths via second harmonic conversion of the Ti:Sapphire and OPO Signal beams. In this arrangement, a combined gap-free and highly flexible tuning range of 340 – 1600 nm is available. An optional further wavelength extension between 1750 – 4000 nm via the OPO Idler beam is available.   

Chameleon MPX (MPX) extends the wavelength range of Chameleon Ultra II or Vision II and is specifically designed and optimized for nonlinear imaging techniques with an added dispersion pre-compensation feature. Independently tunable pump and OPO Signal range of 1010 – 1340 nm offers dual beam excitation of popular fluorescent probes (e.g., eGFP, mCherry), enabling powerful and truly flexible multimodal imaging.

Figure 11

FIgure 5: Wavelength coverage of different Chameleon OPOs when pumped with Chameleon Ultra II. Other pump options are available.


Levante IR fs OPO is an automated, powerful OPO designed to be pumped with a fixed wavelength beam and provides a wide tuning range in the regions of 1320 – 2000 nm (Signal) and 2170 – 5000 nm (Idler). This makes it an ideal OPO to extend the wavelength coverage of Chameleon Discovery NX providing a versatile tool for spectroscopy, materials science, or microscopy applications. Levante IR fs OPO can also be pumped by our high-power Axon 1064 nm model. Even longer wavelengths up to 15 µm can be achieved when combining Levante OPO with additional accessories.

Figure 12

FIgure 6: Extensive spectral coverage by Chameleon Discovery and wavelength extension accessories.


Key features of the femtosecond OPOs  

Full specifications and detailed information about all our femtosecond OPOs can be found in our Ultrafast Laser Oscillators family of products.       




Chameleon Compact OPO 

Chameleon Compact OPO VIS 

Chameleon MPX 

Levante IR fs OPO



Pump laser 

Ultra II / Vision II 

Ultra II / Vision II 

Ultra II / Vision II 

Discovery NX / Axon 

Signal tuning range1 (nm) 

1000 to 1600 

1000 to 1600 

1010 to 1340 

1320 to 2000 

Idler tuning range (nm)

1750 to 4000 

1750 to 4000 

2170 to 5000 

Integrated Second Harmonic Range (nm) 

340 to 540 

500 to 800 

1. Pump laser dependent


OPO Accessories

To extend the parameters window for our femtosecond OPOs, further compatible accessories can be considered.  



Harmonics SHG for the OPO

Second Harmonic Generation units are available for all our OPOs for either signal or idler ranges. As with all Harmonics units, these are fully motorized with software controlled high precision stepper motors and integrated walk-off compensators, allowing high consistency and excellent pointing stability when tuning the wavelength. Carefully selected nonlinear crystals and other optics allow high conversion efficiencies and ultra-wide wavelengths coverage.     

Harmonics DFG for the OPO

This Difference Frequency Generator (DFG) module can greatly extend the spectral coverage of the Levante IR fs OPO and provide access to femtosecond pulses across the mid-infrared (from 4.8 to >15 microns) by mixing the signal and idler outputs. The user-friendly design features an integrated beam overlap and delay line. The output wavelength can be easily tuned by adjusting the OPO Signal. 


FIgure 7: Typical wavelength coverage of a DFG unit used with Levante OPO pumped by a Chameleon Discovery NX laser.


Schedule a no-cost consultation to discuss your needs.