Microfluidic reaction chamber with a reaction chamber circuit

An apparatus comprising:

• a microfluidic reaction chamber configured to contain a reaction fluid for amplification of nucleic acids, the microfluidic reaction chamber including a base wall defined in part by a substrate, a top wall parallel to the base wall and defined in part by a transparent lid, a first side wall perpendicular to the base wall and defined in part by the transparent lid, and a second side wall perpendicular to the base wall and defined in part by the transparent lid;
• and
• a reaction chamber circuit disposed within the microfluidic reaction chamber, the reaction chamber circuit including a top surface parallel to and proximal to the top wall of the microfluidic reaction chamber, a bottom surface parallel to and distal to the top wall of the microfluidic reaction chamber and separated from the base wall of the microfluidic reaction chamber to form a gap between the bottom surface of the reaction chamber circuit and the base wall of the microfluidic reaction chamber, a first side wall parallel to the first side wall of the microfluidic reaction chamber, and a second side wall parallel to the second side wall of the microfluidic reaction chamber;
• wherein the top surface of the reaction chamber circuit, the bottom surface of the reaction chamber circuit, the first side wall of the reaction chamber circuit and the second side wall of the reaction chamber circuit are in fluidic contact with the reaction fluid, and the bottom surface of the reaction chamber circuit includes a photodetector separated from the base wall of the microfluidic reaction chamber by the gap and configured to detect a fluorescence signal from a labeled fluorescent tag in the reaction fluid.