BALM (Backside Absorbing Layer Microscopy) is a new surface imaging optical techinque.


BALM is a wield field optical imaging technique with ultra high sensitivity and full optical resolution.
BALM is implemented on an inverted optical microscope.
BALM uses special windows ("ARA windows") that are used to support the sample or to close the bottom side of a fluidic cell.
BALM addresses samples deposited on the ARA window or very close to it.


BALM specifications

  • In situ imaging (water or air)
  • Real time (video rate)
  • XY (lateral) resolution: better than 250 nm
  • Z (vertical) sensitivity: better than 0,1 nm
  • White light, compatible with any light source
  • Occupies only the lower half space - can be coupled with any technique or accessory implemented on the upper half space over the sample: fluid cell, chemical reagents, biological probes, added electrodes, microprobes, scanning tips, optical tweezers…


ARA window characteristics

  • Composition: “ARA surface” on glass slide (ARA = Anti-Reflecting Absorbing)
  • Diameter: 25 mm
  • Thickness: 170 µm
  • Available ARA surface materials: gold, silica
  • ARA surface material possibilities: metal, semi-conductor, metal oxide, carbon, polymer, graphene and analogs, conductive polymer






The BALM is useful whenever one needs to:

  • Detect molecular layers on solid surfaces especially metallic (in air and in water)
  • Visualize local changes or defects in molecular layers
  • Visualize tiny changes on solid surfaces, either conducting or dielectrics, in almost any environment
  • Visualize electrical and electrochemical activities on surfaces at a molecular scale
  • Visualize the contact between a solid and a biological organism
  • Detect and localize isolated nanoparticles


At the same time, the BALM is useful to:

  • Probe in situ kinetics in any of these situations
  • Combine optical imaging with a high resolution technique on the same sample