A system, comprising: a modulation frequency source configured to generate a modulation frequency voltage; a modulated light source configured to generate a modulated light signal based on the modulation frequency voltage; a specimen measurement system configured to direct at least a portion of the modulated light signal incident upon a specimen for measurement of one or more properties of the specimen, wherein the specimen measurement system is configured to generate a plurality of measurement currents pursuant to the measurement of the one or more properties of the specimen, wherein the specimen measurement system, comprises: a reference detector configured to generate a first current of the plurality of currents, the first current being related to an intensity of the incident light signal; a reflectance detector configured to generate a second current of the plurality of currents, the second current being related to an intensity of a light signal reflected by the specimen in response to the incident light signal; and a detector configured to generate a third current of the plurality of currents based on an electrical signal generated by the specimen in response to the incident light signal; a signal conditioner configured to generate a plurality of measurement voltages from the plurality of currents, respectively; a data acquisition circuit configured to: sample and digitize the plurality of measurement voltages to generate a plurality of measurement digital signals; receive the modulation frequency voltage from the modulation frequency source without the modulation frequency voltage being converted into optical domain; and sample and digitize the modulation frequency voltage to generate a reference digital signal, wherein the sampling of the measurement voltages and modulation frequency voltage are performed in a substantially simultaneous manner; and a computing device configured to perform software-based coherent detection of the measurement digital signals using the reference digital signal. a modulation frequency source configured to generate a modulation frequency voltage; a modulated light source configured to generate a modulated light signal based on the modulation frequency voltage; a specimen measurement system configured to direct at least a portion of the modulated light signal incident upon a specimen for measurement of one or more properties of the specimen, wherein the specimen measurement system is configured to generate a plurality of measurement currents pursuant to the measurement of the one or more properties of the specimen, wherein the specimen measurement system, comprises: a reference detector configured to generate a first current of the plurality of currents, the first current being related to an intensity of the incident light signal; a reflectance detector configured to generate a second current of the plurality of currents, the second current being related to an intensity of a light signal reflected by the specimen in response to the incident light signal; and a detector configured to generate a third current of the plurality of currents based on an electrical signal generated by the specimen in response to the incident light signal; a reference detector configured to generate a first current of the plurality of currents, the first current being related to an intensity of the incident light signal; a reflectance detector configured to generate a second current of the plurality of currents, the second current being related to an intensity of a light signal reflected by the specimen in response to the incident light signal; and a detector configured to generate a third current of the plurality of currents based on an electrical signal generated by the specimen in response to the incident light signal; a signal conditioner configured to generate a plurality of measurement voltages from the plurality of currents, respectively; a data acquisition circuit configured to: sample and digitize the plurality of measurement voltages to generate a plurality of measurement digital signals; receive the modulation frequency voltage from the modulation frequency source without the modulation frequency voltage being converted into optical domain; and sample and digitize the modulation frequency voltage to generate a reference digital signal, wherein the sampling of the measurement voltages and modulation frequency voltage are performed in a substantially simultaneous manner; and sample and digitize the plurality of measurement voltages to generate a plurality of measurement digital signals; receive the modulation frequency voltage from the modulation frequency source without the modulation frequency voltage being converted into optical domain; and sample and digitize the modulation frequency voltage to generate a reference digital signal, wherein the sampling of the measurement voltages and modulation frequency voltage are performed in a substantially simultaneous manner; and a computing device configured to perform software-based coherent detection of the measurement digital signals using the reference digital signal.