User:Pranav Rathi/Notebook/OT/2012/09/21/Fiber light for Olympus microscope

Introduction

I have invented a fiber-light system for Olympus microscope IX71. This system is compatible to Olympus power supply TH4-100. The system has 4 parts: Olympus power supply, Dolan Jenner fiber bundle, fiber-feeder and illuminator & fiber plugin adapter. Fiber plugin adapter can be directly mounted on the illuminator and the whole system can be controlled through Olympus power supply. I designed it such that it requires lest amount of machining and regular tools and components available in any optics lab.

Motivation

Why fiber-light when Olympus illuminator works fine? Following reasons why fiber-light became important:

• DNA experiments are really sensitive to temperature (thermal energy) even few degrees make a big difference.
• Microscope (optical trap) is enclosed inside an enclosure (to avoid airborne noise and currents), so within few hours temperature of the microscope wall rises almost twice due to the halogen lamp used for illumination, this heats up the entire enclosure so as the sample.
• Temperature hike may make two similar data sets which are taken some time apart different.
• Fiber light solves the problem of temperature hike by providing clean light and by removing heat production through the lamp and conduction through the microscope skin.
• With fiber light temperature inside the enclosure goes from 23.7 to 25.5 total 1.8 degree Celsius hike in comparison to halogen lamp where temperature goes from 23.7 to 49 total 25.3 degree hike over a period of 10 hours (see slide 3).

There are many good fiber-light feeder available in market by Dolan Jenner . The reason I made my own is the following:

• Olympus power supply is better designed to feed the illuminator and I wanted something which I can control through Olympus hardware. The feeder I designed can be directly controlled through Olympus power supply.
• I used Dolan Jenner fiber-feeder (fiber-lite model 3100) but it was not good enough for two reasons: For intensity I could only choose 3 settings in comparison to Olympus where I can choose any intensity, fiber-lite probably uses half rectifier because I was seeing flickers in the camera in comparison to Olympus where the intensity was smooth and constant.
• Design and construction: I designed the system such that I would have to do least amount of machining with all the components are available in normal size optics lab just as mine, take less time to make, it took me around 10 hours to make it work including troubleshooting all the bugs and costs be around $400 including my time.
• Optical trap is very sensitive to mechanical vibrations; I wanted to have something which does not have fan inside, because fan vibration can travel through the fiber bundle to the microscope and to the sample. In this design I mount an external fan mounted above the optical table so no physical contact to the fiber-feeder.

Design & Construction

Fiber-light system has four parts (sees slide 5):

1. Olympus power supply model TH4-100
2. Dolan Jenner optical fiver bundle
3. Fiber-light feeder
4. Illuminator & fiber plugin adapter

Components

Please see the slides; all the components are labeled with their part number and company. Power supply is from Olympus and fiber bundle is from Dolan Jenner.

Illuminator & fiber plugin adapter

• Illuminator & fiber plugin adapter has 2 parts. Illuminator is from Olympus and it comes with all the microscopes in some form or other based on the design.

Fiber pluging adapter

• 2 X ER2-thorlabs 2 inches cage assembly rod
• 2 X S1TM08-thorlabs lens cell adapter
• 2 X CP02-thorlabs cage plate
• 1 X AD11F-thorlabs adapter
• 1 X SM1L03-thorlabs lens tube
• 1 X (2.5 X .5 inches) aluminium metal plate
• some 4/40 screws.

Fiber-feeder

• Fiber-feeder has 4 parts:Box, Lamp mount, lens assembly and fiber outlet adapter.
• I used 6X3X2.5 inces aluminum box, 4 rubber legs and 2 banana connectors and 2 leads. Any size box can be used with any mind of connectors.

Lamp Mount

• Halogen lamp came out of Olympus illuminator
• PCB plates (ceramic is better for this purpose, but i couldn't find any)
• Aluminium plates (have to be machined to fit the lamp)
• Some 3/8 nuts and bolts

Fiber outlet adapter

• 2 X CP02T-thorlabs cage plate. Use 2 cage plates back to back, do not use wood.
• 2 X SM1T2-Thorlabs coupler
• 2 X SM1A1-Thorlabs adapter

Lens assembly

• 2 X CP02T-thorlabs cage plates
• 2 X ER2-thorlsba 3’’ cage assembly rod
• 1 X LA1131-A thorlabs f50mm lens
• 1 X TR2-thorlabs post
• 1 X RA90-thorlabs post clamp
• 1 X TR075-thorlabs pos
• Some 1/4 and 3/8 screws

Some parts i might have forget to list so go to the slides for more information. I have not included the tools considering no special tools are used besides normally available tools in the lab.

Design

Illuminator & fiber plugin adapter

The plugin adapter is designed such that it can fit inside the illuminator, so the illuminator optics can be used without putting any external optics for the fiber. The plugin is designed such that the fiber can be inserted or removed by the screws and the whole adapter can be installed or removed without making any changes to the original form of the illuminator, for an example If i do not want to use the fiber-light I can remove it through the holding screws, install the lamp and housing back and restore the original illuminator in seconds. The two cage plates provide the z-adjustment to put the fiber outlet in the focus of the lens.

Fiber-feeder

The are many good ways to design the fiber-feeder. I designed it such because i did not want to buy any hardware, i want to use the hardware available in my lab. A good design would be using a parabolic mirror/retro reflector setting over lens setting where most of the light is collected. In current setting i loose most of the light but what ever light i collect i can focus it very tightly and still have more than enough light. I have to blow the lamp hardly over 50%. In current settings the lens assembly works like 3-D stage and let me focus the spot over the fiber opening with great accuracy. There are no fans so in any optical setup where vibration are killer this setup is ideal, even though i would still recommend a fan installed externally like I did with no physical contact.

Fiber-feeder is connected to the power supply with banana connectors and uses the same lamp as the illuminator. Fiber outlet adapter is on a xy translation cage plate for the last little adjustments. The fiber can be inserted through the opening.

Construction

Power Supply

I start with Olympus power supply slide 5. Identify and label the ground and +12ve pins with multi-meter and turnoff and unplug the power supply wait few minutes. Prepare 1 to 2 meter long banana connector wire depending on the requirement. Insert the open ends into the pins identified and tape it (keep the power supply off all times).