• pE-4000
  • pE-4000
  • pE-4000 Control Pod


NEW GENERATION LEDs The pE-4000 sets the standard as the universal illumination system for fluorescence microscopy.  The system has 16 selectable LED wavelengths across 4 channels that can be matched to the filters and fluorophores of almost any microscope, making it the broadest spectrum of illumination available. 

The CoolLED pE-4000 now benefits from our award winning sustainable Green technology and delivers enhanced intensity at your microscope sample plane with a significant reduction in energy consumption, and is supplied with a 3 year warranty after registration.

The NEW Enhanced pE-4000 is a powerful 4-channel high-specification LED illumination system. It is flexible, controllable and environmentally friendly.  Benefits include:


  • Choice of 256 wavelength combinations from 16 installed LEDs (365nm -770nm)
  • Choose 1 of 4 wavelengths for each 4 channels on the control pod
  • Unique wavelength grouping concept (see below)
  • Optimum wavelength to suit your experiment
  • Specific wavelength characterisation for optimal optogenetic control of cell responses

Wavelength Grouping Concept

As the first company to introduce LEDs into fluorescence microscopy, CoolLED has developed a comprehensive understanding of the complexities of configuring and selecting filter sets for samples which have multiple stains.  These ’multi-band’ filters must have a corresponding absorption and emission band for each stain and the bands must be kept spectrally separate to ensure there is no overlap.

Chroma filter 89402






DAPI/FITC/TRITC/Cy5 Quad filter excited by pE-4000 at matched wavelengths shown above.

CoolLED’s innovation comes from recognizing that all the stains used in multi-band work can have their absorption bands divided into four separate groups across the spectrum due to the restricted bandwidth available.  This has allowed the development of a patent-pending, wavelength-grouping concept which makes it possible to deliver more power in an efficient four channel system.

Wavelength grouping graphic without logo

With its unique 16 selectable LED wavelengths, the pE-4000 ensures optimum compatibility with all single and multi-band filter sets.  The flexibility and extensive functionality of the pE-4000 broadens the range of illumination options in core facilities.

The pE-4000 allows multiple experiments with varying wavelengths on the same sample , as shown here.

(A) Representative photocurrent traces of a PhobosCA expressing CA1 cell evoked with different activation wavelengths and shutoff with 595nm light

(B) Photocurrent traces in the same cell evoked with 460nm light and shutoff with indicated wavelengths (10mW/mm2)

Wietek et al (2017) Anion-conducting channelrhodopsins with tuned spectra and modified kinetics engineered for optogenetic manipulation of behaviour,  Scientific Reports volume 7, Article number 14957(2017) doi: 10.1038/s41598-017-14330-y



  • Lowest Power Consumption – other LED technology uses 120-350 Watts
  • Long lifetime
  • Highly stable, repeatable LED technology
  • Market leading energy efficiency


  • Optimal illumination through control features to extend fluorescence of cells
  • Reduced photobleaching and phototoxicity
  • Microsecond switching
  • Variable pulse duration on/off

“When you can only control intensity of ‘white’ light (rather than individual channels), the level of photobleaching can be high.  With the pE-4000, we can control the excitation of the individual channels.  It is possible to optimise the excitation intensity according to the labelling, greatly reducing photobleaching and phototoxicity in a live experiment.”    Dr Yan Gu, University of Sussex

“Suddenly, we were able to offer users uninterrupted extended live cell experiments of 100+ hours, without worrying about brightness fluctuations, lamps burning, room heating, etc. Also, users have reported markedly reduced bleaching and phototoxicity in their samples, both from the prokaryotic and the eukaryotic research fields.”     Dr Jens Eriksson, Oslo University Hospital



  • Advance integration into major microscope software platforms
  • Save wavelength combinations and return to previous set-up
  • USB interface
  • High speed TTL Triggering
  • Analogue control – dynamic intensity sinusoidal control option
  • White light control
  • Expansion Box
  • Individual channel intensity control
  • Pre-determined intensity saving option






  • High signal to noise ratio which gives cleaner images and data

“Striking, bright fluorescence images with a strong signal to noise ratio even when using a low magnification objective”                           Graham Wright, Institute of Medical Biology, A*STAR Singapore



Time series of a confluent sheet of keratinocytes migrating during a live-cell imaging outgrowth assay, acquired on an Olympus IX-83 microscope equipped with a CoolLED pE-4000 Light Source (Fig. 4). Scale bar = 150 μm






    • Fits to all major research and clinical microscopes
    • Delivers light through a liquid light guide or fiber
    • Offers inline removable excitation filter holders
    • Uses the Universal Collimator


pE-4000 filter holders  pE-Universal Collimator with adaptors


      • Assured through experience and QA assured processes
      • 3 year Warranty after registration
      • First year Warranty swap

The compact pE-4000 Light Source houses all the LEDs, their combining optics, thermal management and control electronics.  A dual mode control pod gives manual control in either White or Advanced modes.  Light is delivered to the microscope by either a single liquid light guide (LLG) or fiber.  LLGs can be used in conjunction with CoolLED’s pE-Universal Collimator which can accept a microscope adaptor from CoolLED’s extensive range.

For further information go to the Downloads tab.

The pE-4000 offers:-

  • Broadest LED spectrum available: 365-770nm – match LED peaks to existing microscope filters
  • Four channel wavelength-grouping design matches with all commercially available dual, triple, and quad filters
  • Individual control of selected LED wavelengths – less background, no filter wheel or shutters
  • Integrated with many imaging software packages - can be incorporated into all experimental parameters
  • Instant on/offno shutters required, no warm up or cool down
  • Stable & repeatable – reliable and consistent results
  • Wide range of Microscope Adaptors – fits most microscopes
  • Precise intensity control in 1% steps (0-100%) – no ND filters required
  • Excellent uniformity over field of view – fixed and stable, no alignment necessary
  • Long lifetime – expected to exceed 25,000 hours of operating time


  • Pre-sets allowing lab manager to match white spectrum to existing filter cubes
  • Higher contrast images from matched-white spectrum
  • Simple to fit, simple to use
  • No training required


  • Individual LED wavelength selection
  • Rapid switching between LED wavelengths enables capture of high speed events
  • TTL & USB interfaces with imaging packages
  • Excitation filters can be fitted in optical path for controlled switching with no moving parts
  • Analogue inputs for dynamic intensity control
  • Optical feedback for applications requiring higher stability
  • Internal function generator for electrophysiology and optogenetics applications

Power requirements

110-240V a.c. 50/60Hz, 2.5A

Power consumption

Standby (i.e. no LEDs on) : Max 7W
Single wavelength operation : Max 25W
Dual wavelength operation : Max 44W
Triple wavelength operation : Max 53W
Quad wavelength operation : Max 60W


pE-4000 Light Source: 150mm(w) x 220mm(d) x 260mm(h) - Weight 3.5kg
pE-4000 Control pod: 154mm(w) x 135mm(d) x 40mm(h) – Weight 0.95kg
pE-4000 Power Supply: 164mm(w) x 64mm(d) x 35mm(h) – Weight 0.58kg
pE-Expansion Box: 151mm(w) x 18mm(d) x 95mm(h) - Weight 0.34kg

Environment & Safety

  • Mercury-free & Laser-free
  • Energy Efficient
  • Long lifetime (25,000 operating hours)
  • No bulb replacements
  • Reduced risk of eye damage
  • Quiet operation
  • No special disposal regulations or issues

Warranty System =24 months extendable by free product registration.  LEDs = 36 months

Dual function remote manual control pod for White mode or Advanced mode

Via USB for independent on/off and intensity control of each channel. Triggering speed approx 1ms
Via 4 TTL inputs for independent on/off control of each channel. Triggering speed <20us
Via single TTL for on/off control of manual or software selected channels
Via 4 analogue inputs 0-10V, 0-300kHz for dynamic control of intensity from external analogue signals

Synch Out:
4 TTL outputs for each channel – active high 1 TTL output for any channel – active high

Programmable interface:
4 TTL outputs for on/off control of peripherals (transmitted illuminators, stages etc.) 4 analogue outputs for intensity control of peripherals (can be programmed to mirror LED intensities for channel control) 0-10V full scale.

Function Generator:
Internally generated sine, pulse and ramps for each channel programmed via control pod.

USB (B type) for PC connection. All other TTL and Analogue inputs/outputs via 25way 'D-type' female connector (optional rear mounting pE-Expansion Box available for BNC connectivity).

Imaging Software:
Recognised under common software e.g. Micromanager, MetaMorph, cellSens, NIS Elements, etc. see Imaging Software

The pE-4000 can be configured to deliver light to the microscope via a single liquid light guide or fiber.

pE-4000-L-SYS-ZZ:   pE-4000 Light Source with manual control pod, and power supply for LLG delivery
pE-4000-F-SYS-ZZ:   pE-4000 Light Source with manual control pod and power supply for Fiber delivery
pE-4000-EB25D:   Rear mounting pE-Expansion Box for 25-way D-type to BNC connectivity
pE-4000-EFH-4:   Set of four Excitation Filter holders (25mm dia.)
pE-6501:   USB-TTL Conversion Kit
pE-1906:   1.5m long, 3mm diameter liquid light guide
pE-10400-YYY:   pE-Universal collimator for use with a single liquid light guide and customer specified adaptor. 

A range of fibers is available from CoolLED, go to Accessories tab To specify microscope code (YYY), see Adaptors To specify Power Cable (ZZ):  10 = Australia, 20 = Europe, 30 = UK, 40 = USA

CoolLED pE-4000 Leaflet

CoolLED pE-4000 User Manual

CoolLED pE-4000 Accessories

CoolLED pE-4000 Declaration of Conformity 

pE-4000-EB25D:   Rear mounting pE-Expansion Box for 25-way D-type to BNC connectivity
pE-4000-EFH-4:   Set of four Excitation Filter holders (25mm dia.)
pE-4000-L-MODULE:   Interchangeable Light Delivery Output module for LLG (3mm dia.)
pE-4000-F-MODULE:   Interchangeable Light Delivery Output module for Fiber (SMA/FC fittings)
    Download leaflet here
pE-6501:   The pE-6501 is a USB controlled TTL trigger box which allows seamless integration of the pE-4000 into major software packages e.g. cellSens, MetaMorph & uManager. It also enhances the existing control in these software packages by allowing TTL control.
    Download the leaflet here



CoolLED’s pE-4000 illumination system can be configured to accept a fiber via either an SMA or FC connector for connecting a wide range of fibers. The user can source the fiber independently or request supply from CoolLED by specifying:-

Diameter in um (AAAA)
Numerical Aperture in mm (0BB)
Length in metres (C)
Termination 1 i.e. SMA, FC or C60- cleaved 60mm bare (DDD)
Termination 2 i.e. SMA, FC or C60-cleaved 60mm bare (EEE)


Product Code: pE-FAAAA-0BB-C-DDD-EEE

Examples below:-

pE-F50-022-2-SMA-SMA:   50 um diameter, .22 Numerical Aperture, 2m long fiber with two SMA terminations
pE-F50-022-2-FC-C60   50 um diameter, .22 Numerical Aperture, 2m long fiber with one FC termination and one 60mm cleaved end

I just purchased a pE-4000 to replace an old version of Lumencor Sola SE on a live imaging microscope. After comparing the power level of the systems, I am convinced that pE-4000 provides stronger illumination at objective. As the Sola light source can only control intensity of ‘white’ light (rather than individual channels), we have to choose the excitation level according to the dimmest labelling fluorophore. The other channels are in turn exposed to unnecessary high dose of excitation. The level of photo-bleaching can be high as a result. With pE-4000, we can control the excitation of individual channel. It is possible to optimise the excitation intensity according to the labelling, greatly reduced photo-bleaching and photo-toxicity in a live experiment. Due to the difference in excitation spectrum with Sola, I was worried about the extra cost of changing dichroic, excitation and emission filters. The options of four wavelength in each channel (totally four channels) enables me to pick up the correct wavelength according to the old filter/dichroic settings. 

Dr. Yan Gu, Manager, Analytical and Quantitative Light Microscopy Facility, Genome Damage and Stability Centre, University of Sussex


"Conceptually, the pE-4000 seems an extremely versatile tool that blends seamlessly with our range of microscopes, making it ideal for high end life science applications.  It is also very user friendly and powerful."

Dr Alex Gardiol, PhD, Imaging Specialist, Olympus Microscopy

"Throwing out the old mercury lamp and exchanging it for the pE-4000 on one of our live cell wide field microscopes has been an astounding success! It allowed us to cheaply breathe new life in to old equipment. Suddenly, we were able to offer users uninterrupted extended live cell experiments of 100+ hours, without worrying about brightness fluctuations, lamps burning, room heating, etc. Also, users have reported markedly reduced bleaching and phototoxicity in their samples, both from the prokaryotic and the eukaryotic research fields. As a facility manager I am also pleased with the instruments ease of use, and shallow learning curve for new users. Taken together with reduced overall microscope maintenance, the pE-4000 has already saved me a substantial amount of time in my daily work life, and improved the quality of our services at the same time."

Dr. Jens Eriksson, Manager, Superresolution Microscopy Core Facility, Dep. Clinical Biochemistry, Oslo University Hospital. 

"I am very impressed with the brightness and performance of the CoolLED pE-4000 in comparison to the mercury or halide light sources for fluorescence.  I also really like it's neat packaging and it is easy to set up and configure.  Absolutely brilliant upgrade for archaic mercury set ups!"

Dominic White, Area Sales Manager, Carl Zeiss Microscopy GmbH  

"I have been imaging using the new CoolLED PE-4000 system on our epi-fluorescent microscope. This is an excellent system as it covers a very wide spectrum of wavelengths. I have found it very easy to use. The user interface is much better as the different LEDs can be changed using the handheld control- without switching off and unscrewing the LAMs as had to be done on the old PE-2 system. In addition the LEDs can be changed dynamically while the software to capture the image is open and also a huge combination of different wavelengths can be used at the same time.
I have also found that the light source from this system is considerably stronger than from the previous system - I now image at 50% strength, when I used to image at 100%. I anticipate using this imaging system a lot more now that the new LED light source is there."

Alison Reynolds, PhD Research Fellow, UCD Conway Institute, University College Dublin 

"Our group is currently attempting to isolate and stain circulating tumour cells. In order to identify these cells we need a minimum of four colour fluorescence imaging, requiring the slide to be scanned using four different LEDs.
To stitch our images together after scanning we require a transmission light microscope image. The image co-ordinates of the light microscope image are used to stitch the fluorescence images together. The previous light source (PE-2) allowed only three LEDs to be used together for our purposes. This meant that when we have multiple slides there are two options to get the full four fluorescence scan: 1)    Change the LED after scanning in Brightfield and three fluorescence channels – this risks damage to the LED itself and is time consuming. It involves un-screwing a panel each time and screws can be damaged or lost relatively easily. It places demand on the ribbon that is connected to the LED and, over time, may damage the ribbon also. We usually scan multiple slides and prefer to use option two, to reduce wear and tear on the light source. 2)    This option is to scan all slides in Brightfield and three colour fluorescence and then go for a second batch of images in both Brightfield and the final fluorescence channel. This is also time consuming, as setting up each scan in focus takes time. It, also, requires a lot more downstream processing to line the images up with one another, as the scans are often of two different sizes. With the new PE-4000 light source I was able to scan four slides in Brightfield and four fluorescence channels in three hours. Four slide took six hours to scan on the previous light source, due to double the number of scans and changing the LED. It has also reduced the downstream processing of the images, as they are all taken using the same co-ordinates, in one batch. Our project aims to expand from four colour fluorescence to six or seven channels over the coming years. Using the old light sources this would require a minimum of three but possibly four scans taken from different positions per slide and would take hours per slide. The current light source meets the needs of researches using modern immunofluorescence techniques as most projects have moved from single to a multi-marker approach, in recent years."

Anthony Cooney, PhD Student, Department of Histopathology, Trinity College Dublin.

I have been using a pE-4000 for optogenetic experiments using in vitro slices for just over a year now.  The pE-4000 has been fantastic for my needs: the ability to simultaneously use multiple wavelengths of light has allowed me to carry out experiments using two different opsins to study how external inputs converge on hippocampal interneurons. I’m currently setting up my own research group at the University of Exeter, and all of my patch-clamp rigs will have a pE-4000 on them, as they are such versatile devices for optogenetic experiments.

Dr Michael Craig, Research Fellow, University of Exeter Medical School