Lambda DG-4 plus / DG-5 plus

The Lambda DG-4plus/DG-5plus is a complete illumination system offering speed and versatility for experiments requiring rapid wavelength switching. The instrument retains all the advantages of interference filter based systems, yet eliminates the temporal constraints imposed by traditional filter changing devices like filter wheels. Switching between any two wavelengths is achieved in less than the 1.2msec vertical retrace period of a video signal, allowing the user to perform real-time video imaging. The high switching speed of the Lambda DG-4plus/DG-5plus facilitates the ability to follow fast changes in ion concentrations in dual wavelength ratio imaging applications and to monitor other concomitant changes in the studied system at additional wavelengths. Narrow bandpass systems, such as single cavity interference filters, grating monochromators, and A.O. modulators, pass unwanted harmonics  of the desired wavelength. Also, with variable wavelength devices, it is not always possible to obtain sufficient blocking of out-of-band wavelengths. Modern interference filters, as used in the Lambda DG-4plus/DG-5plus , do not pass harmonics and have integral blocking characteristics 1000 times better than typical monochromator systems. For the same full width at half maximum (FWHM), interference filters have a narrower spectral bandpass than monochromators due to the absence of the slit function. The dual galvanometer design of the Lambda DG-4plus/DG-5plus allows tuning of the relative intensities at each wavelength. This adjustment is difficult to obtain in variable wavelength devices with a single optical path. Unlike monochromators and other wavelength selective systems, the Lambda DG-4plus/DG-5plus can be used as a source of white light when required.

HOW IT WORKS

This unique optical design of the Lambda DG-4plus/DG-5plus is based on dual scanning galvanometers utilizing interference filters for wavelength selection. The light from the xenon arc lamp is focused on the first galvanometer mirror which directs it via a parabolic mirror, through one of the interference filter channels. Following the filter, a second parabolic and a second galvanometer mirror collect and redirect the light into the light guide. A cold mirror in the beginning of the light path eliminates the IR radiation, reducing significantly the amount of heat absorbed by the optics and the sample. Cold mirrors modified to pass near-IR to 780 to 880nm are also available.A built-in shutter function allows reduction of light intensity by five to six orders of magnitude. For applications requiring mechanical shuttering, like time lapse experiments or very sensitive samples, the SmartShutter™ can be integrated into the device to assure that the light is completely blocked. The standard system, the Lambda DG-4plus holds up to four 25mm interference filters. The Lambda DG-5plus, a five filter version, accommodates three 18mm and two 25mm filters. While the switching time between any two wavelengths is done in less than 1.2msec, the dwell time at any wavelength is arbitrarily set by the user. In addition to the features of the standard Lambda DG-4plus/DG-5 plus, the digital technology used in the Lambda DG-4plus/DG-5plusprovides 0.5msec switch-ing times between adjacent filter positions.The liquid light guide can be coupled to the illumination port of most microscopes using an adapter which can be purchased separately. Please ask for further information.

FEATURES

Complete system for wavelength switching
The Lambda DG-4plus/DG-5plus is a complete integrated 175 (or 300) Watt light source and wavelength switching excitation system.
Four or five interference filters can easily be installed in the DG-4plus or DG-5plus, respectively. An additional standard neutral density filter inserted in the common path of the light.
The light guide output from the Lambda DG-4 / DG-5 provides uniform spatial illumination, as well as vibration isolation from your microscope.
A cold mirror assembly eliminates ir radiation, extending the lifetime of the optics and the light guide, and preventing the exposure of the sample to ir when white light is necessary.

Integral shuttering
The Lambda DG-4plus/DG-5plus provides a high speed shutter function with open/close times of 500µs. the shutter function reduces light intensity by 5 to 6 orders of magnitude.
If complete light shuttering is required, a mechanical shutter (i.e. Smartshutter™) can be incorporated into the Lambda DG-4/DG-5.

Integral neutral density filtering
The Lambda DG-4 plus/DG-5plus provides a high speed shutter function with open/close times of 500µs. the shutter function reduces light intensity by 5 to 6 orders of magnitude.
If complete light shuttering is required, a mechanical shutter (i.e. Smartshutter™) can be incorporated into the Lambda DG-4plus/DG-5plus.
Direct insertion of neutral density optical filters is also possible in the filter holders at any of the four optical channels. A final neutral density optical filter can be placed in the exiting light path which will reduce the light output from all optical channels.

Two outputs for monitoring filter position
A 4 bit TTL signal transmits the current optical channel (filter) position.
A digital-to-analog converter (DAC) output produces a voltage showing which filter is in use.

Turbo blanking
The turbo blanking feature is designed for sitiuations when the switching is done between non-adjacent filter positions. When the instrument is in this mode, the input and output galvanometer mirrors move out of sync, thus preventing the sample form being exposed to light of unwanted wavelength during switching and shuttering.

METHODS OF CONTROL 

Direct computer control via parallel or serial interface
When operated in this mode, the Lambda DG-4plus/DG-5plus control commands are a subset of our Lambda 10-2 controller and will operate with software written for the Lambda 10-2.
(If you plan to control the DG-4 with other interfaces, please ask for specific issues.)

Strobe-pulsed ring buffer control
A sequence of up to 32 filter values can be loaded into a ring buffer via keypad or computer. the system will switch to the next filter in the buffer on a ttl level (trigger) strobe pulse. After executing the last filter change in the string the system resets to the first filter and continues.

Video sync pulsed ring buffer control
In this mode, a video sync pulse can be used to initiate and/or execute the filter change for a sequence of filter values stored in the ring buffer.

Video sync with strobe low
In this mode, the system will implement a filter change on the video sync pulse, but only if the strobe line is held low. this allows a computer to override the sync pulse.

SPECIFICATIONS
   
Lamp Type      300 W ozone free or full spectrum xenon arc bulb
Output Range      330 nm to 700 nm - Ozone free
                           200 nm to 65 0nm - Full spectrum (requires ozone removal)
Lamp Life      expected lifetime 1000 h  (All bulbs have a prorated warranty for 500 h)
Power Consumption     350 W
Filter Diameter      DG-4plus: Four 25 mm filters (1 inch)
                           DG-5plus: Two 25 mm filters and three 18 mm filters
Dimensions      25 cm × 25 cm × 48 cm
Light Guide       2 m long , 3 mm wide
Weight     20 kg
Electrical     115/230 V; 50/60 Hz  power line

ORDERING INFORMATION

BASIC SYSTEM
DG-4plus/OF30      DG-4plus with ozone-free 300 W bulb
DG-4plus/FS30*      DG-4plus with 300 W full spectrum bulb
DG-5plus/OF30      DG-5plus with ozone-free 300 W bulb
DG-5plus/FS30*      DG-5plus with 300 W full spectrum bulb 

*WARNING: The full spectrum Xenon arc bulbs produce ozone, which is toxicand has to be eliminated. Systems containing full spectrum bulbs have to beconnected to an ozone removing device or system. Please contact Sutter Instrument for more information.

ACCESSORIES

O661301                 Ozone free 300 W xenon bulb (useful wavelength range 330 - 700 nm) 
O661300                 Full spectrum  300 W xenon bulb (useful wavelength range 200 - 650 nm) 
DG-IF                     Interference filter holder (25 mm)
DG-IF/18                 Interference filter holder (18 mm)
DG-ND                    Neutral density filter holder

Mounting Adapters for Nikon, Zeiss, Leica and Olympus microscopes are available.