Tip-enhanced Near-field Optical Microscope

I designed and built this system: A Confocal Microscope combined with Bruker Innova AFM working as Tip-enhanced Near-field Optical Microscope.

This was the first version. I am building many versions of it.

AFM resolution 1nmConfocal 1.3 µm (measured) at 1.3µm wavelength, .4NA objective and 1AU apertureTENOM 20nm (measured)

System

Innova AFM

Acto-S confocal microscope

Acto-S Confocal MicroscopeActo-S is a confocal microscope developed to work with any AFM but it could be used without AFM. In the present system it could be used by itself to produce confocal images using external detector and AFM hardware - software (by routing detector signal through AFM hardware) or with AFM to produce confocal images with AFM images. It could also be used for PL and spectral imaging. In this system an IR version of Acto-S was used with 1.3µm laser.

TENOM

TENOM was achieved by top illumination and collection of AU coated Si probe-tip in contact mode. The system could produce AFM and near-filed images side by side in a single scan with near filed resolution up to 20nm.

CMOS camera W/O IR filter

3D Stage with super stability

Flexible adapter for easy slide removal (microscope)

Some Results

AFM Near-field Confocal

The sample under test was a reference target for AFM calibration: 10µm pitch with 200nm depth. Images-512X512

Software-NanoDrive Innova (Bruker)

Software-IR Camera (by me)

I wrote this software. It is used for IR laser spot alignment with probe-tip for optimum near-field enhancement.

Software-IR Laser Control (by me)

Alignment is very crucial for tip enhancement. To facilitate an easy alignment of laser spot with tip I wrote this laser control software which could control the laser in CW or pulse mode with any desired duty cycle.

By: Pranav Rathi (PhD)Scanning Laser Confocal Microscope