Multiphoton Detection Unit

Multiphoton Detection Unit for integration with the Scientifica Slicescope Pro motorised microscopy system.

The Scientifica Multiphoton Detection Unit is a miniaturized, optimized two-channel fluorescence collection and detection system designed for multiphoton fluorescence imaging which is compatible with the SliceScope.

The system comprises a main unit housing pre-aligned optics, safety shutters / switches, a filter cube, and either one or two photo-multiplier (PMT)-based detection modules.  Each detection unit contains a power supply and pre-amplifier.  A control unit is provided to adjust the sensitivity of the two detectors.

Where can it be used?

Above the sample, collecting reflected fluorescence using the microscope objective that also carries the stimulation laser beam.

Below the sample, collecting transmitted fluorescence using a high-NA oil-immersion condenser lens.

It is possible to use two systems simultaneously on one microscope for optimum signal collection in up to four channels.

At this time data acquisition, laser beam scanner and near IR laser are not available direct from Scientifica.

Please note that all dimensions and specifications detailed here are subject to change as this product progresses through the development process. Please discuss this with your sales representative before making critical decisions.

Multiphoton Detection Unit for integration with the Scientifica Slicescope Pro motorised microscopy system.

The Scientifica Multiphoton Detection Unit is a miniaturized, optimized two-channel fluorescence collection and detection system designed for multiphoton fluorescence imaging which is compatible with the SliceScope.

The system comprises a main unit housing pre-aligned optics, safety shutters / switches, a filter cube, and either one or two photo-multiplier (PMT)-based detection modules.  Each detection unit contains a power supply and pre-amplifier.  A control unit is provided to adjust the sensitivity of the two detectors.

Where can it be used?

Above the sample, collecting reflected fluorescence using the microscope objective that also carries the stimulation laser beam.

Below the sample, collecting transmitted fluorescence using a high-NA oil-immersion condenser lens.

It is possible to use two systems simultaneously on one microscope for optimum signal collection in up to four channels.

At this time data acquisition, laser beam scanner and near IR laser are not available direct from Scientifica.

Please note that all dimensions and specifications detailed here are subject to change as this product progresses through the development process. Please discuss this with your sales representative before making critical decisions.

Features and Benefits 

• Compact: Retains a small footprint enabling you to mount other equipment,e.g. manipulators, close to your microscope.
• Easy to use: Simple to switch light paths with just the flick of a switch.
• Standard optics: Enabling you to use standard filters and mirrors(36x25x1mm) and no need to buy expensive custom parts.
• Mounts to the focus arm: Ensures the detectors remain the same distance from the objective.
• You are in control: You are able to customise your multiphoton microscope to suit your application without the need to custom build parts or having to “make do”with other “off the shelf” options.

The detection unit is miniaturised and slim so that maximum access is afforded to the sample for manipulators and electrodes. The unit bolts directly to the focusing mechanism of the SliceScope and carries the objective so that it is always at the best possible position for collecting fluorescence. Alternatively, the unit may be fitted below the (oil immersion) condenser. The system may be configured with either one or two detection units.

Objectives and Condensers

The system is compatible with large aperture wide-field objectives which are preferred for two-photon imaging. These objectives attach directly to the unit for optimum collection efficiency: this enables better image quality at greater depths within thick, scattering samples.

RMS threaded water-immersion objectives (such as X40 / NA 0.8) can be used, and may be fixed or fitted in a motorized objective changer.

The system is compatible with objectives from Olympus and other manufacturers for maximum user flexibility.

The system can be used under the sample stage by means of an oil-immersion condenser (such as the Olympus U-AAC).

The multiphoton detection unit is compatible with large back aperture objectives (A) or with two RMS thread objectives with a Motorised Objective Changer (B)

A custom optical system has been optimized for efficient collection from high-aperture wide-field objectives with two detection ports.

The design is optimized to remove any artifacts that may result from movement of the scanned beam so that the background is more uniform.

The system is designed to minimize the ingress of stray light for best possible sensitivity and dynamic range. This permits imaging at greater depths or with weaker fluorophores.

All optical components are pre-aligned and fixed. No user adjustment is required.

The user may insert conventional fluorescence filter sets, housed in an Olympus filter cube, to optimize signals and differentiate between different fluorophores.

A high-efficiency near-IR blocking filter and visible-reflecting dichroic mirror used at the input to cut out stray laser light from the signal path.

The dichroic mirror can be withdrawn from the beam to permit access for conventional fluorescence imaging and then replaced without disturbing the sample.

The system incorporates a safety shutter that seals the optical system when the dichroic mirror is withdrawn.

Two spectral responses will be available:

Type A has optimal quantum efficiency in the blue-green region whilst providing adequate response in the red.

• Ideal for users whose primary target is weakly-expressed blue-green fluorophores (including GFP and EGFP).
• Optimal when large objectives are used with transmission in the blue-green region less than in the yellow-red region.
• Gives excellent results when used with yellow / red dyes at concentrations typically used to fill patched cells.
• Very low dark current

Type B has enhanced red sensitivity at the expense of some blue-green sensitivity.

• Ideal for users whose primary fluorophores are weakly-expressed orange / red emitters.

A system can be configured with either type of PMT, or with one of each for optimum performance across the whole wavelength range.

One or two detector modules may be fitted to the system. The user may add a second module in the field. Each compact detector module houses a photo-multiplier with integrated high voltage supply, active high-linearity divider chain and pre-amplifier with active filter.

The preamplifier is sited very close to the PMT for best high-speed response and lowest possible noise, to generating the cleanest possible image.

Each module delivers a pre-filtered output via a coaxial connector that can be fed into a data acquisition system. There are no excessive high-frequency noise components to degrade the signal and there is sufficient bandwidth to accommodate rapid image scanning. (0.5 ms per line).

The gain is independently controlled for each detector (using the control unit) to optimize signal levels from different fluorophores in the one experiment. The controller displays the high-voltage being applied to each PMT.

Safety interlock switches are incorporated that cut off the PMTs if the user should open the filter compartment or withdraw the dichroic mirror. Acting together with the safety shutter, the switches ensure that the PMTs are protected from possible damage.

The optical design permits the use of conventional Koehler illumination in the visible or the near IR using a filament lamp or LED illuminator. A video camera may be used on the microscope with a suitable tube lens and users may apply Dodt contrast enhancement.

The transmitted laser beam that passes through the sample may be collected from the rear of the microscope and used (with or without a contrast enhancing technique) to make an image of the sample. This requires an auxiliary detector (which will be made available shortly).

By withdrawing the input dichroic mirror, full access to the sample is gained for conventional fluorescence imaging.

> Download the Multiphoton Detection Unit brochure