THE transportation of optical images has been carried out hitherto with the aid of lenses or mirrors or both. As with all optical systems, aberrations are introduced and the parts have to be aligned ...

Julia Kagan is a financial/consumer journalist and former senior editor, personal finance, of Investopedia. Ebony Howard is a certified public accountant and a QuickBooks ProAdvisor tax expert. She ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...