Multi-wavelength operation of optical disk drives for chemical and biological analysis

Optical disk drives have lasers that operate at 405, 650, and 780 nm making these devices attractive for a wide variety of analytical applications. Here we demonstrate the use of super audio compact disks (SACDs) and computer optical disk drives for multi-wavelength chemical measurements. As an example, dual-chemistry chlorine sensing films were formulated using combinatorial techniques and deposited onto SACDs. The chlorine response was measured at the analytical wavelength (780 nm), while thickness variations were normalized using the response at the 650-nm reference wavelength where the sensing films were not affected by chlorine exposure. Compared to a single-wavelength readout, this dual-wavelength approach improved the linear correlation coefficient (R2) from 0.76 to 0.95 and the limit of analyte detection from 600 to 300 ppb. The use of multi-wavelength optical disk drives should enable chemical and biological sensing with the expanded diversity of sensing chemistries and the advantages of multi-wavelength spectral processing.