I am currently working with a slice-wise SVI parametrisation of the implied volatility surface.
$\sigma^2(x,t) = a_t + b_t (\rho_t (x - m_t) + \sqrt{(x - m_t)^2 + \theta^2})$
Does anyone have experience with interpolation in parameter space? Is it possible to interpolate the implied volatility between maturities by interpolating the parameters and evaluating this "new" slice? Also is there a paper on the topic?
I have so far not been able to find one.