hATR Microscope | MicroIRE Setup

Internal Reflection for Micro-IREs

The stage is aligned for micro-IREs to be externally reflecting off the bottom terraces of the microgrooves. We have developed an optical/geometrical analysis and calculator in the hATR Wizard to guide internal reflection positions for microIREs. The XYZ and D translations are unique to each IRE material, microgroove geometry and microscope set angle. Input the following information about the micro-IRE into the hATR Wizard: material, size - including thickness, groove depth, facet positioning. The IRE is translated towards the source in Z (decreasing stage Z) and away from the source in X (increasing stage X). The D-rail will also be moved away from the source. Both translations may be completed with buttons in the Wizard.

Procedure

Staff will guide you through the following steps to set up your system for measurements.

1. Determine external reflection reference position. For microIREs, this is the center point of a terrace (bottom of groove) of the IRE.
   Find the appropriate z/d positions for external reflection on IRE base – use mirror / flip IRE / use sample area away from terrace features for focus

2. Place crystal in holder, ensure proper alignment – IRE seated into holder, IRE face angle perpendicular to beam path, holder fastened to stage adapter plate, stage adapter plate properly seated to stage.
   Find the x position where the beam is centered on the IRE terrace – use visible laser / FPA / MCT / QCL signals as feedback

   1. Set Current Stage Position to XYZ External Reflection

   2. Set Current Rail Position D External Reflection

3. Enter the details for your sample into the hATR Wizard:

   1. IRE and Microscope Settings:

      1. IRE material real refractive index
         Sample keep at 1
         IRE face angle (custom°)
         Microscope set angle (35°)

      2. MicroIRE Geometry Settings (in mms):

         IRE height (thickness)
         IRE gap (width between edge of terraces)
         IRE terrace (width of base in between grooves)
         IRE ledge (distance from IRE/sample surface to groove apex)

      3. ⚠️ Verify the delta positions are suitable for your system. The values are calculated in micrometers. The Wizard will calculate the required crystal and collection optics translations to align your sample into internal reflection.

      4. Translate the crystal in XYZ and the collection optics in D using the Move buttons.

      5. Verify proper focus and proceed to measurements.