  A broad range of scientific and industrial disciplines require precise
optical measurements at very low light levels. Single-photon detectors
combining high efficiency and high time resolution are pivotal in such
experiments. By using relatively thick films of NbTiN (8-11\,nm) and improving
the pattern fidelity of the nano-structure of the superconducting nanowire
single-photon detectors (SNSPD), we fabricated devices demonstrating superior
performance over all previously reported detectors in the combination of
efficiency and time resolution. Our findings prove that small variations in the
nanowire width, in the order of a few nanometers, can lead to a significant
penalty on their temporal response. Addressing these issues, we consistently
achieved high time resolution (best device 7.7\,ps, other devices
$\sim$10-16\,ps) simultaneously with high system detection efficiencies
($80-90\%$) in the wavelength range of 780-1000\,nm, as well as in the telecom
bands (1310-1550\,nm). The use of thicker films allowed us to fabricate
large-area multi-pixel devices with homogeneous pixel performance. We first
fabricated and characterized a $100\times100\, \mu m^2$ 16-pixel detector and
showed there was little variation among individual pixels. Additionally, to
showcase the power of our platform, we fabricated and characterized 4-pixel
multimode fiber-coupled detectors and carried out photon correlation
experiments on a nanowire quantum dot resulting in $g^2(0)$ values lower than
0.04. The multi-pixel detectors alleviate the need for beamsplitters and can be
used for higher order correlations with promising prospects not only in the
field of quantum optics, but also in bio-imaging applications, such as
fluorescence microscopy and positron emission tomography.
